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Practical Manual on

OF CROP PLANTS

A.K. Chhabra DEPARTMENT OF PLANT BREEDING, CCSHAU, HISAR 125 004

A Practical Manual on

FLORAL BIOLOGY of Crop Plants

A.K. Chhabra

2006 Department of Plant Breeding CCS, Haryana Agricultural University HISAR 125 004

© 2006 Author reserves the rights that no part of the manual can be reproduced for any purpose without his permission. The improvements in the contents of manual would be done by author himself in general interest of larger readership as and when possible.

FOREWORD

Agricultural scientists have the responsibility to increase food production and therefore, food security using genetic and management options. Plant Breeders have engaged themselves in genetic manipulations through conventional plant breeding techniques since ages. They need to be well conversant with the various steps in the act and science of Plant Breeding. He has to perform several operations, right from the choosing of parents for hybridization to the ultimate development of a new variety and its seed production. Plant breeding products include varieties, hybrids and improved populations. Since beginning (when Babylonians and Assyrians practiced pollination in date palm as early as 700 BC), the fascinating subject of floral biology has attracted attention of botanists all over the globe to discover and understand flower structure, modes of reproduction and mechanisms governing cross- and self-pollination. This exciting subject of research has been in the domain of taxonomists/botanists. However, it is a plant breeder who can make the best use of knowledge generated by them to develop high yielding varieties of crops with value added traits, and thus contribute to the food security. Plant breeders need to have sound knowledge of floral biology (flower structure, anthesis etc.) modes and mechanisms of reproduction in crop plants so as to manage directed gene flow within and between species and related wild and weedy forms. This Practical Manual on Floral Biology of Crop Plants has been prepared to provide the reader with detailed flower structure of important field crops (Wheat, Rice, Barley, Pearlmillet, Maize, Cotton, Brassica, Castor, Sesamum, Linseed, Lentil, Field Peas, Mung Bean, Sorghum, sugarcane etc.) and some of the potential underutilized crop plants like Jojoba and Guayule. The exquisiteness of this manual is that it contains high quality detailed digital pictures of flower parts of different crop plants to facilitate the reader to understand plant’s reproductive structure and biology. Dr. A.K. Chhabra, Professor of Plant Breeding, the author of this Manual, has done an admirable job by compiling this information which will not only be useful to the undergraduate and postgraduate students but also to the researchers. I congratulate the author for preparing this comprehensive Manual.

Hisar October 12, 2006

D.C. Gupta Dean, College of Agriculture CCS Haryana Agricultural University, Hisar 125 004

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PREFACE Understanding of Floral Biology (flower structure and anthesis including pollen viability and stigma receptivity) is of utmost importance for the success of any breeding programme to develop elite genotypes and ultimately the varieties for commercial cultivation by the farmers for food security and to improve their economy. The present manual, “Practical Manual on Floral Biology of Crop Plants” is an attempt in this direction to teach undergraduate and postgraduate students the details of flower structure and their reproductive biology and procedures of emasculation and pollination to integrate perfection and precision in gene transfer through conventional plant breeding procedures involving artificial hybridization. Moreover, the contents of the manual also go with the course curricula of UG courses (PB 201 and PB 202) and PG course PB 501. This Practical Plant Breeding Manual will also be quite useful in imparting relevant practical instructions to those who wish to embark on practical plant breeding as their profession. Author of this manual has attempted to provide a systematic reading into the generalized flower structure, its types, preparation of floral diagrams and formula, and detailed floral morphology of 26 crops namely Wheat, Maize, Rice, Barley, Isabgol, Greengram, Pigeon pea, Chickpea, Field peas, Castor, Brassica spp., Sesamum (til), sunflower, Sugarcane, Oats, Pearl millet, Cotton, Sorghum, Groundnut, Linseed, Lentil, Cowpea, Berseem and Ocimum (tulsi) and underutilized plants like Jojoba and Guayule. The manual is illustrative and quite informative. It includes more than 375 excellent digital pictures and hand drawn sketches explaining minutes of flower structure and also a Glossary Section explaining the technical terms used in the text. The author wishes to thank Dr. D.C.Gupta, Dean, College of Agriculture and Dr. R.S. Waldia, Professor and Head, Department of Plant Breeding, for their constant encouragement, guidance and inspiration in the preparation of this Manual. Critical suggestions, moral boosting and ever encouraging attitude of Dr. R. K. Behl, Professor, Plant Breeding enabled me to prepare and improve the quality of this Manual. The author is also thankful to Dr. Somveer for his dedicated involvement all the times for capturing the photographs for this manual and to Dr. Yogesh Jindal, Incharge, Computer Centre (COA) for providing necessary facilities and Mr. Sanjay Sehgal for his timely help whenever required during the course of preparation of this manual. The financial assistance received from CCS Haryana Agricultural University, Hisar in the form of ICAR Development Assistance Funds for publication of this Manual is gratefully acknowledged. Hope this will be useful to the students and researchers alike pursuing the sacred mission of crop improvement.

Hisar October 12, 2006 A.K. CHHABRA

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Contents Sr. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Title

Foreword Preface An introduction to flower structure Performa for Description of A Flower Floral Biology of crop plants: 1. Wheat (Titicum aestivum L.) 2. Rice (Oryza sativa L.) 3. Oats (Avena sativa L.) 4. Pearl millet (Pennisetum glaucum R.Br.) 5. Maize (Zea mays L.) 6. Sorghum (Sorghum bicolor L. Moench) 7. Sugarcane (Sacchrum officinarum L.) 8. Cotton (Gossypium spp.) 9. Chickpea (Cicer arietinum L.) 10. Pigeonpea (Cajanus cajan L. Millsp.) 11. Fieldpeas (Pisum sativum) 12. Groundnut (Arachis hypogeae L.) 13. Rapeseed and Mustard (Brassica spp.) 14. Sunflower (Helianthus annus L.) 15. Linseed (Linum usitissimum) 16. Lentil (Lens culinaris) 17. Berseem (clover) (Trifolium alexandrium L.) 18. Green gram (mung bean) (Vigna radiata) 19. Barley (Hordeum vulgare L.) 20. Cowpea (Vigna unguiculata /sinense L. Walp.) 21. Isabgol (Plantago ovata) 22. Jojoba (Simmondsia chinensis) 23. Guayule (Parthenium argentatum) 24. Ocimum (Tulsi) (Ocimum basilicum L.) 25. Castor (Ricinus communis L.) 26. Sesamum (Til) (Sesamum indicum) Annexure I-Glossary Annexure II- General features of flowers of in- and out-breeders and old and new family names Annexure III- Crops and Their Time of Anthesis References and Suggested Reading

Page No. i ii 1-29 30-41 42-239 42-48 49-54 55-61 62-74 75-80 81-88 89-04 95-107 108-115 116-123 124-130 131-141 142-154 155-163 164-171 172-176 177-182 183-187 188-192 193-198 199-204 205-210 211-214 215-223 224-230 231-239 240-248 249 250 251-256

INTRODUCTION TO FLOWER STRUCTURE INFLORESCENCE 1.

Racemose: Inflorescence with monopodoal branching i.e., the inflorescence axis continues to grow and gives off lateral and axillary flowers.

(i)

Raceme: Racemose inflorescence having a common axis and stalked flowers arranged in acropetal succession, e.g., Brassica. Panicle: Axis of raceme is branched. Spike: Inflorescence is similar to raceme but the flowers are sessile: e.g., Achyranthes aspera. Spikelet: Very small spike of a compound spike forming a unit; e.g., grasses. Catkin (or Ament) : A pendulous spike or spike-like inflorescence consisting of small unisexual flowers ; e.g., Morus alba. Spadix : A spike with thick and fleshy axis covered by a large spathe ; e.g., Maize. Corymb : It is a modified raceme with relatively a short main axis, in which the lower flowers have much elongated pedicels so that the flowers come to the same level ; e.g., Candytuft. Umbel : It is a modified raceme, in which the flowers have stalks (pedicels) of nearly equal length and they seem to arise from the same point at the apex of peduncle, e.g., onion. Compound umbel : An umbel with branched axis, each unit umbel is called umbellule ; e.g., Coriander. Capitulum (Head) : A dense concave, convex, spherical or flat-topped inflorescence of numerous sessile flowers clustered on a common disc or receptacle. A capitulum is usually subtended by an involucre of bracts ; e.g., Compositae (Asteraceae) family, e.g., sunflower.

(ii) (iii) (iv) (v) (vi) (vii)

(viii)

(ix) (x)

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RACEME

SPADIX

PANICLE

SPIKE

SPIKELET

CORYMB

UMBEL

CATKIN

CAPITULUM

KINDS OF RACEMOSE INFLORESCENCE After Pradewep

1. Some common prefixes used in the description of plants : Number in Latin in Greek One Uni-e.g., unipinnate mon- e.g., monadelphous Two bi-e.g., bipinnate di- e.g., dimerous Three tri-e.g., triangularis tri- e.g., trimerous Four quadri-e.g., quadrangularis tetra- e.g., tetramerous Five quinque-e.g., quinquefolius penta- e.g., pentamerous Six sex-e.g., sexangularis hex- e.g., hexagonal Seven Septem-e.g., Septemlobus hepta- e.g., heptagonal Eight octo-e.g., octoflorus octo- e.g., octoflorus Nine noveme-e.g., novemneris ennea- e.g., ennealobus Ten decum-e.g., secemlobus deca- e.g., decapetalus Single haploe.g., haplostemonous

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Double diplo- e.g., diplostemonous Many multi-e.g., multilocular poly- e.g., polystemonous Outside ecto- e.g., ectophytic Inside endo- e.g., endophytic Within intra-e.g., intrapetiolar Between inter-e.g., interpetiolar 2. Cymose :. An inflorescence with sympodial branching, i.e., the main axis terminates into a flower and lateral branches arise below it which also terminate into flowers. The central flower opens first. Various types of cymose inflorescences are: (i) Uniparous (monochasial) : The main axis ending in a flower producing only one lateral branch at a time, each terminating into a flower. Scorpoid : A uniparous cymose inflorescence where the successive lateral branches develop alternatively on both sides forming a zigzag; e.g., Heliotropium.

Helicoid : A uniparous cymose inflorescence whose successive lateral branches develop towards one side of axis forming a unilateral spiral coil ; e.g., Hamelia patens. (ii) Biparous (dichasial) : The main axis ending in a flower producing a pair of lateral branches which too, terminate into a flower ; e.g., Ixora, Saponaria.

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(iii) Multiparous (polychasial) : The main axis ending in a flower producing more than two lateral branches which too, terminate into a flower ; e.g., Calotropis. (iv) Glomerule : A very dense single cyme with central flower blooming first. 3. Special types: (i) Cyathium : A small, cup-shaped, special type of inflorescence found in Euphorbia with single female (pistillate) flower in the centre and several male (staminate) flowers around it. (ii) Verticillaster : A false whorl, composed of a pair of opposed cymes arising in axils of opposite leaves, as in labiatae (Lamiaceae). (iii) Hypanthodium : A cup-like, fleshy receptacle bearing flowers on the inner wall of the cavity as in Ficus. (iv) Solitary terminal : Flower borne singly at the apex : e.g., Poppy. (v) Solitary axillary : Flower borne singly in the axil of a leaf ; e.g., Cotton, Cucurbita. FLOWER The following terms are used in connection with the description of flower : Pedicel : Stalk of an individual flower. Pedicellate : A flower having a pedicel (stalk), e.g., one of the florets of wheat. Sessile : A flower without a pedicel (stalk). e.g., one of the florets of wheat Staminate : An unisexual flower with stamens. e.g., pearlmillet, maize. Pistillate : An unisexual flower with carpels. e.g., maize. 1. Presence of floral whorls : (i) Complete. A flower having all the four whorls, i.e., calyx, corolla, androecium and gynoecium, e.g., Cotton, Brassica. (ii) Incomplete. A flower lacking one or more whorls, e.g., Wheat. (iii) Hermaphrodite (bisexual or perfect). A flower with both (stamens) and female (gynoecium) organs, e.g., Cotton, wheat, rice etc.. (iv) Unisexual (Imperfect). A flower having only one reproductive whorl (male or female). The unisexual flowers may be – (i) Staminate. Male flower with only androecium, e.g., maize, pearlmillet or (ii) Pistillate. Female flower with only gynoecium. e.g.,maize. (v) Neuter. A sterile flower without androecium and gynoecium, e.g., ray florets of Sunflower. 2. Polygamous, Monoecious and Dioecious Plants (distribution of flower types): (i) Polygamous. Plants having more than two types of flowers (i.e., bisexual, staminate and pistillate), e.g., Mango, Cashewnut, etc. Polygamomonoecious: staminate, pistillate and perfect flowers are on the same plant.

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Flower Structure What is a flower? A flower is a functional unit concerned with reproduction. A flower can be pictured as a very short stem (the receptacle) which holds the components of the flower in sequence at the very tip of this stem, so they appear in the centre of the flower, c/a female organs (the gynoecium). Next to them are the male organs (the androecium) and next to them are the petals (corolla) and sepals (calyx).

Flower Structure Stigma- The receptive part of the female reproductive organ on which pollen germinates. Style-the elongated part of a carpel bearing the stigma, usually at the tip. Ovary-the hollow basal region of a carpel, consisting one or more ovules. Ovules- the structures in the chamber of an ovary containing the egg cell, within the embryosac.The ovules develop into the seeds after fertilization.

Carpel-One of the flower’s female reproductive organs comprising a stigma, a style and an ovary.

Anthers- usually bilobed, contains the pollen. Filament-the stalk bearing the anther

Stamen-the male reproductive organ of a flower consisting of an anther and a filament

Petal- a non-reproductive accessory organ of a flower. This is sterile and usually brightly colored, attracts insect pollinators.

Corollacollective term for all the petals of a flower

Calyxcollective term for all the sepals of a flower

Sepal- a floral leaf or individual segment of the calyx of a flower, generally green, that forms the outer protective layer of a flower bud.

Gynoecium-(=pistil)collective term for all the female reproductive organs of a flower comprising one or more free or fused carpels

Androecium-collective term for all the male reproductive organs of a flower comprising one or more free or fused stamens

Perianth-the floral envelop usually divisible into an outer whorl (calyx) of sepals and inner whorl of petals (corolla).

Receptacle- flat, concave or convex part of the stem from which all parts of a flower arise.

A complete flower is one with all parts (calyx, corolla, androecium and gynoecium) present. A flower lacking one or more of these parts is said to be incomplete. A perfect flower is one with both androecium and gynoecium present. If either are lacking, the flower is said to be imperfect.

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The term polygamomonoecious is used to describe a species population containing plants that are polygamous and plants that are monoecious. Coconut palms provide a good example of a polygamomonoecious species. Polygamodioecious: staminate, pistillate and perfect flowers are on the different plants. Polygamodioecy ensures pollination in the absence of crosspollination. (ii) Monoecious. Plants with unisexual flowers and both staminate and pistillate flowers occur on the same plant, e.g., Maize, Castor, Cucurbits, etc. (iii) Dioecious. Plants with unisexual flowers. A plant bears either staminate or pistillate flowers, e.g., Date Palm, Betel, Mulberry, etc. 3. Floral Symmetry: The shape, size and arrangement of floral appendages (i.e., calyx, corolla, androecium and gynoecium) around the axis of a flower is called floral symmetry. The axis to which the flower is attached is called mother axis. The side of flower towards mother axis is called posterior side and the side away from it is called anterior side. On the basis of floral symmetry there may be following three conditions of a flower: (i) Actinomorphic. A flower with radial symmetry, i.e., the parts of each whorl are similar in size and shape. The flower can be divided into two equal halves along more than one median longitudinal plane, e.g., Hibiscus, Solanum, etc. (ii) Zygomorphic. A flower with bilateral symmetry, i.e., the parts of one or more whorls are dissimilar. The flower can be divided into two equal halves in only one vertical plane, e.g., Pisum sativum, chickpea etc.

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(iii) Asymmetric. A flower which cannot be divided into two equal halves by any vertical plane, e.g., Canna. 4. Arrangement of floral organs : (i) Cyclic. The floral parts are arranged in definite whorls around the axis of flower, e.g., Brassica, Solanum, etc. (ii) Acyclic. The floral parts are arranged in spirals and not in whorls, e.g., Magnolia. (iii) Spirocyclic. Some of the floral parts are in whorls and others in spirals (Half cyclic), e.g., Rose, Ranunculus, etc. 5. Position of floral parts on thalamus in respect to ovary : (i) Hypogynous. The upper part of thalamus is slightly swollen and forms a cushion-like disc. The gynoecium is situated at the top of the thalamus (Thus, the ovary is superior). All other floral parts (i.e., calyx, corolla and androecium) arise below the level of ovary. The condition is called hypogyny, e.g., Citrus, Brassica, etc. (ii) Perigynous. The upper part of thalamus may be of three types - (a) discshaped, (b) cup-shaped, or (c) flask-shaped. In disc-shaped thalamus, the ovary of gynoecium lies in the centre while all other floral whorls occur on the periphery but at the same level, e.g., Pea. In cup- shaped thalamus, the ovary of gynoecium arises from the bottom of cup while all other whorls arise at the rim of the cup, e.g., Prunus. In flask-shaped thalamus, ovary of gynoecium is placed at the bottom of the flask while all other floral whorls are attached at the mouth of the flask. The ovary is half-superior. The floral parts arise from around the ovary and not beneath it, e.g., Rose. The condition is called perigyny.

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(iii) Epigynous. The upper part of thalamus is cup-shaped, flask-shaped or tubular in which the ovary of gynoecium is completely inserted. The wall of ovary is fused with the thalamus. All other floral whorls are borne on the upper part of thalamus. The ovary is inferior and other floral parts appear to arise above its level. The condition is called epigyny, e.g., Cucurbita. 6. Number of floral parts: Occurrence of the same number of floral parts in the different floral whorls of a flower is called isomery and the flower ic termed as isomerous flower. Sometimes, flowers have different number of parts in each whorl. This condition is called heteromerous. The isomerous flowers may be of the following types: (i) Dimerous : Floral parts in 2's or multiple of two. (ii) Trimerous : Floral parts in 3’s or multiple of three. (iii) Tetramerous : Floral parts in 4's or multiple of four. (iv) Pentamerous : Floral parts in 5's or multiple of five. *Dicotyledonous flowers are usually di-, tetra-, or pentamerous whereas monocotyledonous flowers are trimerous.

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Differences amongst Hypogynous, Perigynous and Epigynous flowers HYPOGYNOUS FLOWERS 1. The upper part of thalamus is slightly swollen and forms a cushion like disc. 2. Calyx, corolla and androecium arise below the level of ovary. 3. Ovary is superior while all other parts are inferior. 4. The gynoecium is placed at the top of the thalamus. The wall of ovary is not fused with the thalamus. 5. Calyx, corolla and androecium remain separated from the gynoecium so that the ovary is visible from outside.

PERIGYNOUS FLOWERS 1. The upper part of thalamus may be discshaped, cup-shaped or flask-shaped. 2. Calyx, corolla and androecium arise from around the ovary and not beneath it. 3. Ovary is half-superior.

4. The ovary of gynoecium is placed at the bottom of cup or flask-shaped thalamus where ovary wall is not fused with the thalamus. 5. Calyx, corolla and androecium often develop from a common base. The ovary of gynoecium may or may not be visible from outside.

EPIGYNOUS FLOWERS 1. The upper part of thalamus is usually flaskshaped or tubular. 2. Calyx, corolla and androecium are borne on the upper part of thalamus above the level of ovary. 3. Ovary is inferior while all other parts are superior. 4. The ovary of gynoecium is completely inserted. The wall of ovary is fused with the thalamus.

5. Calyx, corolla and androecium develop jointly from the neck of hollowed out thalamus so that the ovary is not visible from outside.

FLORET A single flower of an inflorescence is called a floret. BRACTS AND BRACTEOLES Bracts are modified leaves which bear flowers in their axils. A flower may be: 1. Bracteate. Flowers having bracts. 2. Ebracteate. Flowers without bracts. The bracteate flowers have the following types of bracts : (i) Leafy bracts. Large leaf-like bracts, e.g., cotton, Adhatoda. (ii) Spathe. Large, often brightly coloured and cover spadix inflorescence, e.g., Banana, Maize, etc.

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(iii) Involucre. A large number of bracts form compact one or more whorls around a flower or an inflorescence, e.g., Sunflower. (iv) Petaloid bracts. Bracts are large, showy and brightly coloured, e.g., Bougainvillea, Euphorbia pulcherrima (Poinsettia), etc. (v) Glumes. Dry and scaly bracts found in association with spikelet inflorescence, e.g., Grasses (wheat, barley. Oats etc.). Bracteole : A secondary bract at the base of an individual flower. Bracteolate : Flower having bracteoles. Ebracteolate : Flowers without bracteoles. Spathe : A single, large bract enclosing the flower cluster, commonly present in spadix. Involucre : A whorl or whorls of bracts around an inflorescence. Each bract is called phyllary. bract Epicalyx : A set of bracteoles forming an additional whorl over the calyx. CALYX Calyx can be of various types based on colour, shape, cohesion, shape, aestivation and duration: 1. Colour : (i) Sepaloid. Green in colour, like a sepal. (ii) Petaloid. Coloured and showy, like a petal.

2. Cohesion: (i) Polysepalous. Sepals are free and separate.

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Cotton Bracts surrounding the cotton boll

(ii)

Gamosepalous. Sepals are fused. Gamosepalous calyx may be toothed (free parts tooth like), fid (fusion upto half), partite (fusion less than half), or connate (fused only at their bases). 3. Shape : (i) Pappus. A few hairy or feathery sepals, e.g., Sonchus, Eclipta. (ii) Spurred. One or more sepals long beak-like, e.g., Delphinium. (iii) Spinous. Sepals modified into spines, e.g., Trapa. (iv) Companulate. Bell-shaped, e.g., Petunia. (v) Cupulate. Cup-shaped, e.g., Gossypium (cotton). (vi) Urceolate. Urn-shaped, e.g., Silene. (vii) Infundibuliform. Funnel-shaped, e.g., Atropa. (viii) Hooded. One or more sepal become hood-like, e.g., Aconitum. (ix) Bilabiate. Differentiated into an upper and a lower lip, e.g., Ocimum. (x) Tubular. Tube-like, e.g., Verbena. 4. Aestivation Aestivation : is the mode or arrangement or sepals in the bud. It is of various types: Valvate : Sepals meeting by their edges and not overlapping or turning. Valvate aestivation may sometimes be: 1. Induplicate : Margins projecting inward. 2. Reduplicate : Margins projecting outward. 3. Involute : Margins rolled inward. Twisted (contorted) : Margins of sepals are overlapping regularly i.e., one margin of a sepal overlaps the next and the other margin is overlapped by a preceeding sepal. Twisting may either be clockwise or anticlockwise. Imbricate: The sepals overlap each other in such a way that one is internal, one is external and the others are partly internal and partly external. Quincuncial : Out of five sepals two are interior, two are exterior and the fifth one has one margin exterior and the other interior.

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5. Duration of calyx : (i) Persistent. Sepals remain attached till the maturation of fruit and do not fall off, e.g., Solanum. (ii) Caducous. Sepals fall off early, e.g., Papaver. (iii) Deciduous. Sepals fall off after fertilization, e.g., Brassica. COROLLA Corolla is of various types based on cohesion of petals, shape and aestivation: 1. Cohesion : (i) Polypetalous. Petals are free and separate. (ii) Gamopetalous. Petals are fused in whorl or in parts. 2. Shape (Fig. 30.16) : (i) Cruciform. The four free petals are arranged in cross-shaped. Each petal has a claw and a limb, e.g., Mustard (Plants belonging to Brassicaceae). (ii) Caryophyllaceous. Five free petals with long claws and with limbs placed at right angles to the claws, e.g., plants belonging to family Caryophyllaceae (Dianthus). (iii) Rosaceous. Five or more free petals spreading regularly outwards and not distinguishable into limb and claws, e.g., plants of family Rosaceae (Rosa). (iv) Papilionaceous. Five free petals are unequal in size (Zygomorphic) and arranged in butterfly like manner - one large posterior bilobed petal called standard (or vexillum) which over-laps two small lateral petals called wings (or alae). The wings further overlap the two innermost smallest and fused petals forming a boat, called Keel (or carina). Examples plants of family Papilionaceae or Fabaceae (Pea, chickpea, pigeonpea etc.). (v) Infundibuliform. Gamopetalous and funnel-shaped, e.g., Petunia. (vi) Campanulate. Gamopetalous and bell-shaped, e.g., Campanula.

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(vii) Tubular. Gamopetalous and tubular or cylindrical, e.g., disc florets of Sun flower. (viii) Hypocrateriform. Gamopetalous with long tube expanding abruptly into flat limbs, e.g., Clerodendron. (ix) Rotate. Gamopetalous with a flat and circular limb at right angles to the short tube (Wheel-shaped), e.g., Solanum nigrum. (x) Bilabiate. Gamopetalous, zygomorphic and two lipped. Bilabiate corolla with two lips closed to one another is called personate, e.g., Antirrhinum. Bilabiate corolla with two lips wide open is called ringent, e.g., Salvia. (xi) Ligulate. Gamopetalous, zygomorphic with a short narrow tube below and flattened above like a strap, e.g., ray floret of sun flower. 3.Aestivation: The mode of arrangement of petals (also sepals) in relation to one another in a flower bud is known as aestivation. It is of the following types (i) Open. Petals of a whorl (or sepals of a whorl) are sufficiently apart from each other.

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(ii) Valvate. Petals of a whorl (or sepals of a whorl) meet by their edges but do not overlap. Valvate aestivation may be sometimes – (a) In-duplicate (Margins projected inwards), (b) Reduplicate (Margins projected outwards) or (c) Involute (Margins rolled inwards).

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(iii) Twisted (or Contorted). Margins of petals are overlapping regularly i.e., one margin of a petal overlaps the next and the other margin is overlapped Ray floret by a preceding petal. Twisting may either be clockwise or anticlockwise. (iv) Imbricate. Margins of petals are overlapping irregularly. Out of five petals, one is completely internal, one is completely external and in each of the remaining three petals one margin is internal and the other is external. (1) Ascending Imbricate. It is a type of imbricate aestivation in which the posterior petal is internal, e.g., plants of family Cassiaceae (Bauhinia, Cassia). (2) Descending Imbricate or Vexillary. It is a type of imbricate aestivation in which the anterior petal is internal. The posterior petal is largest and it almost covers the two lateral petals and the later in their turn nearly overlap the two anterior and smallest petals, e.g., plants of family Papilionaceae or Fabaceae (Pea). (v) Quincuncial. It is a modification of imbricate aestivation in which two petals are internal, two are external and the fifth one has one margin external and the other margin internal. PERIANTH In some plants, there is no distinction between sepals and petals. Such floral whorls are called perianth and the individual parts of the whorls are called tepals. Their description is same as calyx or corolla. The terms are used as - phyllous or tepalous. e.g., polyphyllous or polytepalous (free tepals) , gamophyllous or gamotepalous (fused tepals), etc. ANDROECIUM Collection or group of stamens and staminodes (a sterile stamen) is called androecium. The technical terms concerning androecium are as follows1. Cohesion of Stamens : (i) Monadelphous. All the stamens of a flower are united in one bundle by fusion of their filaments only. The anthers are free, e.g., Hibiscus, Althaea, Abutilon, etc.

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(ii)

Diadelphous. All the stamens of a flower are united in two bundles by fusion of

MONADELPHOUS

POLYADELPHOUS

DIADELPHOUS

SYNANDROUS SYNGENESIOUS

FORMS OF COHESION OF STAMENS

their filaments only. The anthers are free, e.g., Pea (Pisum sativum). They may be 9 fused + 1 free as in case of pulses like peas, gram, arhar etc. and 8 fuses + 2 free as in case of Groundnut. (iii) Polyadelphous. Filaments of all the stamens unite to form more than two groups. The anthers are free, e.g., Citrus. (iv) Syngenesious. Anthers of all the stamens of the flower unite to form a cylinder around the style. The filaments are free, e.g., plants of Compositae or Asteraceae (Sonchus, Sun flower, etc.). (v)

Synandrous. Anthers as well as the filaments are fused throughout their whole length, e.g., plants of family Cucurbitaceae (Cucurbita, Lagenaria, Luffa, etc.).

(vi) Polyandrous. Stamens are indefinite and free, e.g., Ranunculus.

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Difference amongst Monadelphous, Syngenesious and Synandrous Stamens MONADELPHOUS SYNGENESIOUS SYNANDROUS STAMENS STAMENS STAMENS 1. All the stamens of a 1. Anthers of all the 1. Anthers as well as flower are fused in one stamens are fused. filaments of all the bundle by their filaments stamens are fused. only. 2. Staminal tube is formed 2. Fused anthers form a 2. Fused anthers as well as around the base of the tube around the style filaments form a compact pistil which may extend to mass. cover the style. 3. Anthers and upper part 3. Filaments of all the 3. No part of stamens is of the filaments are free. stamens are free. free. 2. Adhesion of stamens : (i) Epipetalous. Stamens adhere to the petals by their filaments and hence appearing to arise from them, e.g., Solanum, Ocimum, etc. (ii) Epitepalous (Epiphyllous). Stamens adhere to the tepals by their filaments and hence appearing to arise from them, e.g., Asphodelus. (iii) Gynandrous. Stamens adhere to the carpels either throughout their length or by their anthers only, e.g., Calotropis. 3. Insertion of stamens: (i) Haplostemonous. Stamens in one whorl, usually as many as the number of sepals or petals. (ii) Antesepalous. Opposite to sepals. (iii) Antepetalous. Opposite to petals. (iv) Diplostemonous. Stamens are arranged in two alternating whorls. The members of outer whorl alternate with the petals, e.g., Cassia. (v) Obdiplostemonous. Stamens are arranged in two alternating whorls. The members of outer whorl opposite the petals, e.g., Pink. (vi) Polystemonous. Statements are arranged in more than two whorls. 4. Size of stamens : (i) Didynamous. Out of four stamens in a flower, two long and two are short, e.g., Ocimum. (ii) Tetradynamous. Out of six stamens in a flower, two outer are short and four inner are long, e.g., plants of the family Brassicaceae (Mustard).

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DIPLOSTEMONOUS

OBDIPLOSTEMONOUS

POSITION OF STAMENS WITH RESPECT TO PETALS 5.

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Position of stamens : (i) Inserted. Stamens shorter than corolla tube. (ii) Exserted. Stamens longer than the corolla tube, protruding outwards. 6. Number of anther-lobes thecae : (i) Dithecous. Anthers have two lobes with four microsporangia or pollen sacs. (ii) Monothecous. Anthers have only one lobe with two microsporangia or pollen sacs. 7. Fixation of anthers : (i) Basifixed (Innate) : Filament attached to the base of the anther, e.g., Brassica. (ii) Adnate. Filament is continued from the base to the apex of anther, e.g., Verbena. (iii) Dorsifixed. Filament is attached to the dorsal (back) side of the anther, e.g., Citrus. (iv) Versatile. Anther is attached lightly at its back to the slender tip of the filament so that it can swing freely, e.g., Bottle brush. 8. Dehiscence of anthers : (i) Longitudinal. Slits appear lengthwise in the anther lobes. Longitudinal dehiscence may be of 3 types – (a)Introrse: Dehiscence occurs towards the inner side (centre) of the flower ; e.g., Leguminosae,

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(b)Extrorse: Dehiscence occurs on the outward side of the flower ; e.g., Papaveraceae, and (c)Latrorse: Dehiscence occurs laterally; e.g., Croton sparsiflorus: (ii) Transverse. Anther lobes dehisce by breadthwise slits formed roughly in the middle, e.g., Lady’s finger (Abelmoschus esculentus). (iii) Valvular. Anther walls break and lifted at places like valves, e.g., Barberry. (iv) Porous. Anther lobes dehisce by apical or basal pores, e.g., Cassia, Tomato, etc. (v) Irregular. Anther walls break irregularly to disperse pollen grains, e.g., Najas.

GYNOECIUM Gynoecium is the collective term for the innermost or central whorl of Floral appendages (i.e., carpel/carpels). A unit of gynoecium is called pistil. Following technical terms are related with gynoecium -

(ii)

1. Number of carpels: (i) Monocarpellary. Gynoecium comprises of a single carpel; e.g., Leguminosae. Bicarpellary. Comprised of two carpels ; e.g., Acanthaceae.

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(iii) (iv) (v) (vi)

Tricarpellary. Comprised of three carpels ; e.g., Liliaceae. Tetracarpellary. Comprised of four carpels ; e.g., Datura. Pentacarpellary. Comprised of five carpels ; e.g., Melia. Multicarpellary. Comprised of many carpels, e.g., Papaver.

2. Cohesion of carpels : (i) Apocarpous. Gynoecium comprised of two or more carpels which are free ; e.g., Ranunculus. (ii) Syncarpous. Gynoecium comprised of two or more carpels which are fused; e.g., Hibiscus. 3. Position of the ovary (i) Superior. Ovary is borne above the point of attachment of perianth and stamens on the thalamus; e.g., Citrus. (ii) Semi-inferior. The condition of ovary is intermediate between superior and inferior; e.g., Rose. (iii) Inferior. Ovary is borne below the point of attachment of perianth and stamens. The thalamus completely covers the ovary and fuses with it; e.g., Cucurbita.

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4. Number of locules: (i) Unilocular. Ovary with one chamber. (ii) Bilocular. Ovary with two chambers. (iii) Trilocular. Ovary with three chambers. (iv) Tetralocular. Ovary with four chambers. (v) Pentalocular. Ovary with five chambers. (vi) Multilocmar. Ovary with many chambers.

5. Placentation type : (i) Marginal. Occurs in a monocarpellary, unilocular ovary. The placenta develops and ovules are borne along the junction of the two margins of the carpel; e.g., Pea. (ii) Axile. Occurs in a bi-or multicarpellary and multilocular ovary. The margins of carpels fold inwards fusing together in the centre of ovary where the placentae are formed. The ovules are borne at or near the centre on the placenta, in each locule ; e.g., Hibiscus.

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(iii) Parietal. Occurs in a bi-or multicarpellary but unilocular ovary. The carpels are fussed only by their margins. The placentae, bearing the ovules, develop by the swelling up of fusing adjacent margins of the carpels. The placentae then appear as internal ridges on the ovary wall ; e.g., Argemone. Ligustieum (iv) Free-central. Occurs in a multicarpellary but unilocular ovary. The carpels are fused only by their margins. The placenta develops in the centre of ovary as an upgrowth from ovary base which bears ovules ; e.g., Primulaceae. The freecentral placentae may also be formed by breaking down of the septa from the initial axile placentation, as in Caryophyllaceae. (v) Basal. Occurs in a bi- or multicarpellary but unilocular ovary. The ovules are few or reduced to one and borne at the base of the ovary ; e.g., Compositae (Asteraceae). (vi) Superficial. Occurs in multicarpellary, multilocular ovary. The ovules are borne on placentae which develop all around the inner surface of the partition wall ; e.g., Nymphaea. 6. Style : (i) Terminal. Style lying in the same straight line with the ovary ; e.g., Hibiscus. (ii) Lateral. Style arising from the side of the ovary ; e.g., Potentilla. (iii) Gynobasic. Style arising from the thalamus, e.g., Ocimum, Salvia. (iv) Stylopodium. A disc-like swelling at the base of the style ; e.g., Coriandrum. 7. Stigma : Capitate. Cap-like globose head ; Discoid : Disc-shaped ; Plumose : Feather-like ; Dum-bell shaped : Like a dum-bell ; Bifid Forked ; Liner : Long and narrow ; Sticky : Provided with sticky liquid.

Capitat stigma

FRUIT True fruit : Product of a single ripened ovary or a single flower enclosing seeds. False fruit (pseudocarp) : Besides ovary, it also contains parts of other organs viz., receptacle, pedicel, sepals, etc.

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Capitat stigma

Difference amongst Marginal, Parietal and Axile Placentations Marginal Placentation

Parietal Placentation

1. Usually occurs in 1. Occurs in a bi-or monocarpellary unilocular multicarpellary but uniloc-ular ovary. ovary (sometimes two or more locular due to false septa) 2. It consists of a single 2. It consists of two or more longitudinal placenta or longitudinal placenta or files of file of ovules attached to ovules attached to the wall of the ovary. the wall of the ovary. 3. Placenta develops along 3. The placentae develop by the the junction of the two swelling up of fusing adjacent margins of the carpel. margins of the carpels.

Axile Placentation

1. Occurs in a bi- or multicarpellary and bi- or multilocular ovary. 2. It consists of two or more files of ovules attached to a central placenta or axile column. 3. The margins of carpels fold inwards fusing together in the centre of ovary where the placentae are formed.

1. Dehiscent dry fruits. (i) Legume : A dehiscent dry fruit produced from a monocarpellary, superior ovary which dehisces from both the sutures into two valves ; e.g., Pea. (ii)

Follicle : A dehiscent dry fruit produced from a monocarpellary, superior ovary which dehisces from one suture only ; e.g.. Delphinium, Calotropis.

(iii) Siliqua : A dehiscent dry fruit produced from a bicarpellary, syncarpous, superior ovary which is unilocular but appears bilocular due to false septum. Fruits dehisce along both the sutures from base to apex and a large number of seeds remain attached to the replum (septa) ; e.g., Brassica.

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(iv) Capsule: A dehiscent dry fruit produced from syncarpous, superior or inferior ovary which dehisces along two or more lines of suture in various ways (i.e., longitudinal, transverse, porous and by teeth) ; e.g., Datura, Gossypium. 2. Schizocarpic dry fruits. (i)

Lomentum: Fruit is similar to a legume but constricted between the seeds. Dehiscing sutures are transverse. The fruit splits into one seeded indehiscent compartments at maturity; e.g., Tamarindus, Cassia fistula. (ii) Cremocarp : Fruit is produced from a bicarpellary, syncarpous, bilocular and inferior ovary. It is two-seeded fruit which splits longitudinally into two indehiscent mericarps which remain attached to a thread like carpophore ; e.g., Coriandrum. (iii) Regma : The fruit is produced from a bi-or multicarpellary, syncarpous and superior ovary. It breaks up into as many segments or cocci as there are carpels ; e.g., Ricinus, Geranium. (iv) Carcerule : The fruit is produced from a bicarpellary, syncarpous, tetralocular and superior ovary. Each locule contains one seed. The fruit breaks up into four indehiscent parts (nutlets) ; e.g., Ocimum. 3. Indehiscent dry fruits. (i)

Achene : A small, indehiscent, one seeded fruit developing from a monocarpellary ovary and in which the pericarp is hard, leathery and remains free from seed coat; e.g., Mirabilis, Clematis, sunflower etc. (ii) Caryopsis : A small, indehiscent, one seeded fruit developing from a monocarpellary ovary and in which the pericarp is fused with the seed coat. The seed completely fills the chamber ; e.g., Wheat. (iii) Cypsela : The fruit is produced from bicarpellary, syncarpous and ACHENE OF SUNFLOWER inferior ovary http://waynesword.palomar.edu/images/sunfl3b.jpg&imgrefurl=http

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with calyx persistent and forming the 'pappus’. It contains only one seed. The pericarp and seed coat remain free ; e.g., Tridax, Sonchus. (iv) Nut : A large, indehiscent, one-seeded fruit that develops from a bi- or multicarpellary ovary. The fruit wall becomes hard, stony or woody at maturity; e.g., Litchi, Chestnut, Cashewnut. (v) Samara : A dry, indehiscent, one-seeded winged fruit developing from bicarpellary, syncarpous ovary : The wing is modified outgrowth of pericarp ; e.g., Holoptelea integrifolia (Chilbil). 4. Fleshy fruits. (i)

(ii)

(iii)

(iv)

(v)

(vi)

(vii)

Berry: A fleshy, usually many-seeded fruit with massive, pulpy and juicy pericarp produced from a syncarpous ovary. The epicarp of berries generally becomes conspicuously coloured when ripe ; e.g., Tomato, Banana. Hesperidium : It is a berry with a firm, hard and leathery pericarp, as in Citrus. The fruit develops from polycarpellary, syncarpous and superior ovary. Outer glandular skin is epicarp, the white fluffy stuff is mesocarp and inner membrane surrounding the locules is endocarp. The juice is secreted by large multicellular hairs lying towards inner side of carpels ; e.g., Lemon, Orange. Pepo: A large fleshy fruit developing from a tricarpellary, syncarpous, unilocular and inferior ovary with parietal placentation. The fruit is many seeded with pulpy interior ; e.g., Cucumber, Melon. Drupe: A fleshy, one seeded, indehiscent fruit developing from mono or multicarpellary syncarpous ovary. The pericarp is differentiated into outer, thin epicarp (forming skin), middle fleshy and fibrous mesocarp and inner hard and stony endocarp which encloses and protects the seed; e.g., Mango, Coconut, Walnut. Balausta : A fleshy fruit with many chambers and many seeds like the berry. Pericarp forms a firm rind and two rows of carpels are placed one above the other bearing seeds irregularly: Fruit is crowned with the lobes of an adnate calyx- Edible part is testa; e.g., Pome-granate. Amphisarca: A fleshy, many-seedded fruit with a woody pericarp developing from a syncarpous and superior ovary. The edible portion is the placenta and inner pulpy pericarp ; Aegle marmelos. Pome: A fleshy false fruit enclosed within the fleshy thalamus. The fruit develops from bi-or multicarpellary, syncarpous, inferior ovary, e.g., Apple.

5. Aggregate fruits. (i)

Etaerio of follicles : An aggregate of follicles ; e.g., Consolida, Michelia champaca.

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(ii)

Etaerio of achenes : An aggregate of achenes ; e.g., strawberry in which it

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occurs scattered over the enlarged fleshy thalamus. (iii) Etaerio of drupes : An aggregate of drupes; e.g., Raspberry. (iv) Etaerio of berries : Bunch of berries crowded together on a thick thalamus forming a single fruit; e.g., Anona squamosa. 6. Multiple fruits. (i)

Sorosis : The fruit is produced from the entire inflorescence which is spike or spadix in which the flowers fuse by their succulent perianth. The inflorescence axis becomes fleshy by hypertrophy forming a compact mass ; e.g., Jack fruit, Pineapple, Mulberry. (ii) Syconus : The fruit produced from the enitre hypanthodium inflorescence ; e.g., Ficus. (iii) Fabaceae

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Proforma For Description of A Flower INFLORESCENCE: 1. Racemose/cymose/mixed/special 2. Racemose-Typical Raceme/ spike/ compound spike/ spikelet/ catkin/ spadix/ corymb/ umbel/ capitulum. 3. If Cymose-Monochasial (scorpoid / helicoids / dichasial / polychasial. 4. If special-Cyathium / verticillaster / hypanthodium. FLOWER : 1. Pedicellate/sessile. 2. Bracteate/ebracteate ; type of bract. 3. Bracteolate/ebracteolate. 4. Complete/incomplete. 5. Bisexual (hermaphrodite, perfect)/unisexual (staminate/pistillate). 6. Actinomorphic/zygomorphic. 7. Cyclic/hemicyclic (spirocyclic)/spiral. 8. Hypogynous/perigynous/epigynous/nude. 9. Number of floral parts – Dimerous/trimerous/tetramerous/pentamerous. 10. Any special feature – Colour ; size ; anthophore ; androphore ; gynophore ; gynadrophore ; disc ; nectarines. CALYX : 1. Number of sepals. 2. Cohesion – Polysepalous/gamosepalous. 3. Sepaloid/petaloid. 4. Aestivation – Valvate/twisted/imbricate/quincuncial. 5. Caducous/persistent. 6. Modifications, if any.

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COROLLA : 1. Number of petals. 2. Cohesion – Polypetalous/gamopetalous. 3. Shape of corolla – Cruciform/caryophyllaceous/rosaceous/papilionaceous/ campanulate (bell-shaped) tubular/infundibuliform (funnel-shaped)/rotate/bilabiate/ personate/ligulate. 4. Regular/irregular. 5. Aestivation – Valvate/twisted/imbricate/quincuncial/vexillary. 6. Apendages, if nay – spur/nectary/corona. PERIANTH : 1. Number of tepals ; number of whorls. 2. Cohesion – Polytepalous/gamotepalous. 3. Sepaloid/petaloid. 4. Aestivation – Valvate/twisted/imbricate/quincuncial. 5. Any special feature. ANDROECIUM : 1. Number of stamens (write α if more than 10) ; number of fertile, sterile and staminode. 2. Cohesion – Polyandrous/monadephous/diadelphous/polyadelphous/ syngenesious/synandrous. 3. Epipetalous/ epitepalous/ gynandrous. 4. Antipetalous/ dilostemonous/ obdiplostemonous. 5. Didynamous/tetradynamous. 6. Inserted/exerted. 7.Anthers–Dithecous(two celled) / monothecous (one celled). 8. Attachment of anthers – Basifixed/ adnate/ dorsifixed/ versatile. 9. Dehiscence – Introrse /extrorse. 10. Any special feature. GYNOECIUM : 1. Number of carpels – Monocarpellary/ bicarpellary/ tricarpellary/ tetracarpellary/ pentacarpellary/ poly (or multi) carpellary. 2. Cohesion – Apocarpous/syncarpous. 3. Number of locules – uni-/bi-/tri-/tetra-/penta-/multilocular. 4. Number of ovules in each locule. 5. Ovary – Superior/semi-inferior/inferior. 6. Placentation – marginal/axile/parietal/basal/free-central/superficial.

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7. Style – Terminal/letral/gynobasic/stylopodium. 8. Stigma – Number ; shape-simple, lobed, capitate, branched. 9. Any other special feature.

FRUITS : Types of fruits-simple, aggregate or composite. FLORAL FORMULA Floral formula is the summarized account of the floral characters of a plant or a family represented by symbols. The characters and their symbols by which they are represented are as follows – Flower Bracteate : Br. Flower Ebracteate : Ebr. Flower Bracteolate : Brl. Flower Ebracteolate : Ebrl. Actinomorphic : ⊕ Zygomorphic : % Hermaphrodite or Bisexual : Staminate (Male) : Pistillate (Female) : Neuter : N Perianth : P Calyx : K Corola : C Androecium : A Gynoecium : G Number of floral parts are written at right foot of the symbol and if they are fused are bracketed. For example : Sepals five free : K5 Sepals five fused : K(5) Petals six free : C6 Petals five fused : C(5) Stamens ten free : A10 Stamens ten in two whorls of 5 each: A5+5 Stamens indefinite : Aα Stamens 10, diadelphous : A(9)+1 (one group has 9 fused and the other has only 1) Carpels two free : G2 Bicarpellary sycarpous : G(2) Carpels five fused : G(5)

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Epipetalous condition is shown as : Epiphyllous condition is shown as : Superior ovary is shown by a horizontal underline below the number: G2 Inferior ovary is shown as : Perigynous condition is shown as : G2Examples of the floral formulae of some common flowers are given below – Ranunculus scleratus (Fam. Ranunculaceae): Br, Brl, ⊕, , K5, C5, Aα, Gα (Bracteate, Bracteolate, Actinomorphic, Hermaphrodite, Calyx 5 free, polysepalous, Corolla f free, polypetalous ; Androecium, indefinite, free, polyandrous ; Gynoecium polycarpellary, apocarpous, superior ovary). Solanum nigrum (Fam. Solanaceae) EBr, ⊕, +, K(5), C(5), A5, G(2) (Ebracteate, Actinomorphic, Hermaphrodite, Calyx 5 gamosepalous, Corolla 5 gamopetalous, Androecium 5 polyandrous epipetalous ; Gynoecium bicarpellary, syncarpous, superior ovary). FLORAL DIAGRAM The floral diagram is a diagrammatic representation of the pooled up informations from transverse sections of the flower bud in relation to mother axis. It is characterized by the following The axis to which the flower is attached is called mother axis. The side of the flower towards the mother axis is known as posterior side and the side away from it is called anterior side. Mother axis is drawn at the top of the floral diagram in the form of a small circle. Bract is drawn as a single arc on the anterior side (opposite the mother axis). The bracteoles are drawn on both lateral sides. Calyx is drawn as whorl of arcs representing the number of sepals. Corolla is drawn inner to calyx as a whorl of arcs representing petals. Number of sepals and petals are shown by number of arcs. If sepals of petals are free, the arcs are shown free. If they are fused, the margins of arcs arc joined. Aestivation is shown by overlapping of margins. Relation of odd sepal or odd petal with mother axis is also shown in the diagram. Usually the petals alternate with the sepals. Stamens are shown inner to the whorl of petals either in one whorl or in two whorls or arranged spirally. Each stamen is drawn in the shape of kidney. If anthers are dithecous, they are shown as two kidney lobes and if they are monothecous, they are shown as single lobed kidney. Symbols of stamen are drawn separated apart if they are free and joined by solid line if they are fused. The relative position with

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regard to petals or sepals is also drawn in the diagram. If they are epipetalous, the symbols of stamens are joined to petals with solid lines. Gynoecium is drawn in the centre of floral diagram. Apocarpous condition is shown by drawing a number of separate circles. Syncarpous condition is drawn as fused circles representing a transverse section of the ovary. Other features such as placentation, number of locules, number of ovules, swollen placenta, presence of nectaries and disc are shown accordingly.

A representation of floral diagram of Brassica compestris is given in figure below. DESCRIPTION OF SOME FAMILIES FAMILY: BRASSICACEAE (= CRUCIFERAE OR MUSTARD FAMILY) Systematic Position : Class — Dicotyledonae Subclass — Polypetalae Series — Thalamiflorae Order — Parietales Family — Brassicaceae

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Inflorescence

Petal Stamen Pedicel

Floret Fruit

Calyx FLORET Stigma

Petal

Leaf

Stamen

Stem

Style

Sepal

Ovary

Locule RACEME INFLORESCENCE Placenta Anther Lobes

Thalamus

Pedicel L.S. of FLORET Ovule Wall

T.S. of OVARY

Stigma Style Conne -ctive Filam -ent STAMEN

Ovary GYNOECIUM FLORAL DIAGRAM

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Distribution: The family Brassicaceae includes about 375 genera and over 3200 species distributed widely in north temperate regions. Field Recognition: Plants are annual or perennial herbs, rarely shrubby, with a smelling watery juice. Corolla- cruciform, stamen—tetradynamous and fruit siliqua or silicula. Familiar plants: Brassica campestris —Mustard (Sarson), Raphanus sativus — Radish (Mooli), Brassica rapa— Turnip (Shaljam), Brassica oleracea var. botrytis — Cauliflower (Phool Gobhi), Brassica oleracea var. capitata — Cabbage (Band Gobhi), Iberis — Candytuft, etc. Family description: Inflorescence : Typically racemose. Flower : Ebracteate, ebracteolate, pedicellate, complete, hermaphrodite (bisexual), cyclic, actinomorphic, rarely zygomorphic (Iberis), tetramerous, hypogynous. Calyx : Sepals 4, polysepalous, arranged in 2 whorls of 2 each, outer whorl is anterio-posterior. Corolla : Petals 4, polypetalous, cruciform (arranged in a cross), alternate with sepals, often clawed, (petals reduced or scale like in Coronopus and absent in Lepidium). Androecium : Stamens 6, arranged in 2 whorls (2 + 4), polyandrous, tetradynamous (2 outer lateral are long and 4 inner are short), 4 green dot-like nectar glands present at the base of the outer and inner paired stamens, anthers dithecous (rarely monothecous), introrse ; stamens are two in Coronopus didymus, four in some species of Nasturtium, and upto 16 in Megacarpaea pofyandra. Gynoecium: Bicarpellary, syncarpous, ovary, superior, unilocular but becomes bilocular due to false septum (replum), parietal placentation, replum unites the two parietal placentae, ovules many, style 1, stigma 2 (capitate or bilobed). Fruit : Siliqua or silicula. Seed : Small, non-endospermic with large curved embryo, testa often mucilaginous. General Floral Formula : Ebr, Ebrl, ⊕, +, K2+2, C4, A2+4, G(2) Example 1. Brassica campestris (Mustard) Inflorescence. Typical raceme. Flower. Pedicellate, ebracteate, complete, hermaphrodite (bisexual), actinomorphic, cyclic, hypogynous, tetramerous, yellow. Calyx. Sepals 4, arranged in 2 whorls of 2 each, polysepalous outer sepals anterioposterior, slightly petaloid. Corolla. Petals 4, polypetalous, cruciform, valvate aestivation, yellow. 36

Androecium. Stamens 6, arranged in two whorls, polyandrous, tetradynamous (4 inner long and 2 short), anthers dithecous, basifixed, introrse, glands present at the base of 4 long stamens. Gynoecium. Bicarpellary, sycarpous, ovary superior, unilocular but becomes bilocular due to false septum (replum), many ovules in each locule, parietal placentation, style short, stigma bifid. Fruit. Siliqua. Floral formula. Ebr, ⊕, , K2+2, C4, A2+4, G(2). FAMILY : FABACEAE (= PAPILIONACEAE OR PEA FAMILY) Systematic Position: Class — Dicotyledonae Subclass — Polypetalae Series — Calyciflorae Order—Rosales Family—Fabaceae ( = Papilionaceae) Distribution: The family includes about 440 genera and 12000 species distributed all over the world except the arctic regions. Field Recognition : Herbs, shrubs or trees ; leaves simple or pinnate compound with pulvinate base ; flower zygomorphic having papilionaceous corolla ; sepals united, odd sepal anterior ; corolla aestivation descending—imbricate ; stamens monadelphous or diadelphous (1 + 9), carpel one, fruit a pod. Familiar plants : Pisum sativum (Pea), Arachis hypogaea (Ground nut), Phaseolus vulgaris (Kidney bean), Phaseolus aureus (Green gram), Phaseolus mungo (Black gram), Cajanus cajan (Pigeon pea), Cicer aurantium (Chickpea), Glycine max (Soybean), etc. Inflorescence : Racemose or solitary. Flower : Bracteate, sometimes bracteolate, complete, hermaphrodite (bisexual), zygomorphic, cyclic, hypogynous or sometimes perigynous, pentamerous. Calyx : Sepals 5, more or less united in a tube and persistent, odd sepal anterior. Corolla : Petals 5, polypetalous, papilionaceous (i.e., a posterior petal is large and called standard or vexillum, two lateral petals are lanceolate and slightly curved called wings or alae and two anterior petals are fused along the margin to form a boat shaped keel or carina), posterior petal outermost, aestivation descendingimbricate (vexillary).

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FLORAL DESCRIPTION OF SWEET PEAS (Pisum sativum) Tendril Leaflets

Standard Wing

Leaf

Keel

Sigma Style

Stamen Sepal

Stem Flower Foliaceous stipule

Fruit

Ovary

Anthers Ovule

Pedicel L.S. FLOWER

Placenta

A FLOWERING TWIG

Filaments Locule

ANDROECIUM

Wall

Standard Wings

Keel FLORAL DIAGRAM

COROLLA

38

Androecium : Stamens 10, diadelphous (i.e., 9 are fused into a tube and 1 is free), rarely monadelphous, anthers bithecous, introrse and dehisce by longitudinal slits. Gynoecium : Monocarpellary, unilocular, many ovules, marginal placentation, ovary superior, style long bent at its base. Fruit : A legume or pod, rarely a lomentum. Seeds : Non-endospermous. General Foral Formula : Br, %, , K(5), C1+2+(2), A(9)+1, G1 Economic Importance 1. Pulses and Vegetables : The family is the source of several pulse crops such as Pigeon pea (Arhar), Gram (chana), Pea (Matar), Field bean (Bankia), Cluster bean (Gwar), Lima bean (Lobia), Lentil (Masoor), Green gram (Mung), Bean (Sem), Soya (Soybean), Black gram (Urd), etc. 2. Ornamentals : Common ornamentals are lupin (Lupinus), Sweet pea (Lathyrus odoratus), Butterfly pea (Clitoria ternatea), etc. 3. Oil. Seeds of Peanut (Arachis hypogaea) and Soybean (Glycine max) yield oil which is used as cooking oil, preparation of soap, cosmatics, etc. 4. Dye. Indigo dye is obtained from Indigofera tinctoria. 5. Plants belonging to this family are also used as fodder, medicinal value, etc. Example 1. Lathyrus odoratus (Sweet pea) Inflorescence. Racemose or solitary axillary. Flower. Pedicellate, bracteate, complete, hermaphrodite (bisexual), zygomorphic, cyclic, slightly perigynous, pentamerous, variously coloured. Calyx. Sepals 5, gamasepalous, valvate aestivation, green, hairy, persistent. Corolla. Petals 5, polypetalous, vexillary aestivation, papilionaceous consisting of larger posterior petal, the vexillum, two lateral wings (alae) and two petals fused to form the keel (carina). Androecium. Stamens 10, diadelphous, nine fused in the form of a tube around the ovary and tenth, posterior one free, anthers dithecous, basifixed, introrse. Gynoecium. Monocarpellary, unilocular, ovary half-inferior, marginal placentation, style long and curved, stigma capitate, covered by the keel. Fruit. Legume. Floral frmula. Br, %, , K(5), C5 or 1+2+(2), A(9)+1, G1-. FAMILY : POACEAE ( = GRAMINEAE) Systematic Position : Class–Monocotyledone, Series– Glumaceae, Family – Poaceae Distribution : The family is represented by about 620 genera and over 10,000 species distributed throughout the world. Field Recognition : Herbs or shrubs with round stem (culm) having usually hollow internodes ; jointed stem ; leaves mostly flat, 2-ranked (distichous) with distinct open leaf sheath and linear blade with often a ligule at their junction ; flowers reduced

39

enclosed in glumes, perianth represented by lodicules, ovary superior, stigma feathery, fruit caryopsis. Familiar Plants : Triticum aestivum (Wheat), Oryza sativa (Rice), Zea mays (Maize), Saccharum officinarum (Sugar cane) Bamboos, Doob grass, etc. Infloresence : Spikelet ; spikelets are arranged in racemes, panicle or spikes; each spikelet consists of one or more flowers (or florets) and their subtending bracts arranged on rachilla (inflorescence axis), at the base of spikelet are generally present two sterile glumes (lower one called first glume and upper one second glume) ; In some genera either the first glume or both the glumes are absent. Flower : Small, inconspicuous, usually called florets ; Bisexual or unisexual ; zygomorphic ; hypogynous; each floret consists of two bracts (one bract and one bracteole) called lemma and palea ; lemma (fertile or flowering glume) is greenish, keeled or awned, palea (representing bracteole) is thin membranous and bears a flower proper in its axil. Perianth : Absent or reduced to 2 (or rarely 3) minute scale like lodicules. [Inflorescence axis that bears flowers = rachilla ; first bract of spikelet = first glume ; second bract of spikelet ; = second glume ; Bract of flower ; = lemma ; Bracteole of flower = Palea ; Perianth of flower = lodicules] Androecium : Stamens usually 3 (rarely 1 - 6), filaments free; anthers bithecous, basifixed or versatile, introrse ; dehiscence longitudinal. Gynoecium ; Bi— or tricarpellary, Syncarpous, ovary superior, unilocular with one ovule, placentation basal, styles 2 (rarely 1 or 3), stigma feathery or plumose. Fruit : A caryopsis (rarely nut, utricle or berry). Seed : Endospernuc (endosperm starchy), embryo straight. General Floral Formula: ⊕ or %, or or ♀, P2 or 3 or absent, P3 or 1-6, G(2-3). Inflorescence. Spike of spikeletes ; each spikelet encloses 4 flowers and consists of the following parts(i) A pair of barren glumes present at the base, outer one is called first and inner one is called second glume, (ii) an inferior palea (or lemma) is present next to glume towards the anterior side and (iii) a membranous superior palea (or pale) towards posterior side. The glumes are regarded as bracts and palea as bracteoles. Flower. Sessile, bracteate, bracteolate, complete, hermaphrodite (bisexual), zygomorphic, heteromerous, cyclic, hypogynous. Perianth. Tepals 2, rudimentary, membranous, free, called lodicules. Androecium. Stamens 3, polyandrous, 1 anterior and 2 lateral, filaments long, anthers bithecous, versatile, introrse. Gynoecium. Monocarpellary, unilocular, single ovule, ovary superior, basal placentation, style absent, stigma 2, long and feathery. Fruit. Caryopsis. Floral formula.Br, Brl, %, +, P2, A3, G1

40

Awn

Inflorescence

Spikelet Rachis Flag leaf SPIKELET OF WHEAT

feathery stigma

T.S. OVARY

Stem

Ovary

Gynoecium Stamen

PLANT

GYNOECIUM

Anther Lodicule

Lemma

Palea

Connective

Filament

Glume II

Glume I

STAMEN

OPENED SPIKELET

FLORAL DIAGRAM

FLORAL DESCRIPTION OF Triticum aestivum

41

Floral Biology of Wheat Family

: Gramineae

Genus

: Triticum

Species

: aestivum

Genome Formulae for Several Species of Triticum and some of its close relatives: Species Diploid species Triticum boeoticum Triticum monococcum Aegilopes speltoides Aegilopes caudata Aegilopes squarrosa Secale cereale Tetraploid species Triticum dicoccoides Triticum dicoccum Triticum durum Triticum carthalicum Triticum polonicum Triticum turgidum Triticum timopheevi Aegilopes cylindrica

Chromosome no (2n)

Genome formula

Common name

14 14 14 14 14 14

AA AA BB CC DD EE

Wild einkorn Einkorn

28 28 28 28 28 28

AABB AABB AABB AABB AABB AABB

28 28

AAGG CCDD

Wild emmer Emmer Durum wheat Persian wheat Polish wheat Solid stem wheat timopheevi goat grass

42

rye

Chromosome no

Genome formula

Common name

42 42 42

AABBDD AABBDD AABBDD

Club wheat Spelt Common wheat

Species Hexaploid species Triticum compactum Triticum spelta Triticum aestivum

Introduction Wheat is the leading grain crop of temperate climates in the world. It is the second most important food crop in India, after rice, both in terms of area and production. During last few years India has become the second largest producer of wheat in the world. China being at the top in the world, contributing 13 % in area and 19% in production followed by India that contributes 13% in world wheat production and occupies 12% of area. USA, Russia, France Canada, Germany, Turkey, Australia and Ukraine are the other countries that contribute significantly in the world wheat basket. Although cultivated under a wide range of climatic conditions, most extensive production of wheat is in areas where the winters are cool and the summers comparatively hot. In India five species of Figure 2.1: Spike and wheat are grown, T. aestivum (bread wheat), T. durum Rachis of wheat (macaroni wheat), T. dicoccum (emmer wheat), T. sphaerococcum (dwarf wheat), and T. turgidum (rivit wheat). Maximum acreage is planted under bread wheat.

Floral Biology Flower The inflorescence of wheat is called ‘ear’ or ‘head’, (Fig. 2.1) and in botanical language it is called as ‘spike’. This is a compound distichous spike, whose primary axis bears two opposiote rows of lateral spikelets and single terminal spikelet i.e. spikelets are systematically arranged and are distributed along a common axis known

43

as rachis. The main axis of rachis is a sinuous, notched structure and has numerous internodes with narrow base and broader apex. This has a zigzag appearance. There are varietal differences for toughness of rachis, some having tough rachis that does not break even when threshed, others having brittle axis that breaks down when the grains are ripe. Spikelets are arranged in pairs except at the tip where single terminal spikelet is present.

Figure 2.2: Spikelet of wheat

Spikelet (Fig. 2.2 and 2.3) The unit of the inflorescence (spike) is the spikelet. Each spikelet is a condensed reproductive shoot consisting of two subtending sterile bracts or glumes, enclosing 3 to 5 florets and rarely up to 9 florets on a short axis called rachilla (secondary axis). The typical glume is boat-shaped with rounded base. Each floret has two bracts, lemma and palea present opposite to each other. Lemma is a brittle structure which may be awned, (having awns) awnletted (having small awns) or awnless

Spikelet

Gynoecium

Floret

Figure 2.3: Spikelet, gynoecium and floret of wheat

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(without awns) depending upon genotype. Palea on the other hand is a membranous structure and always awnless. Florets (Fig. 2.3, 2.4 and 2.5) Each floret consists of a lemma, a palea, androecium and gynoecium. The lemma enfolds the palea near their attachment point. Awn is the extension of the midrib of lemma in awned varieties. Glumes of different varieties differ in the firmness of attachment to the rachis, in the tightness with which they hold the mature kernels and in size relative to size of the kernels. These characters vary with variety and make them resistant or susceptible to shattering. Wheat spikes also differ in their shape, length, width and degree of compactness. Variability Figure 2.4: Compact and also exists for glume shape, colour and tip. lose spikes of wheat These spike and glume characters are quite stable (genetically controlled and highly heritable) and are commonly used as descriptors in categorization of wheat species and varieties. Androecium and Gynoecium (Fig. 2.6) Florets are bisexual and zygomorphic. Each floret has three stamens with large anthers and a pistil bearing bifid feathery stigma (all cereals except rice Figure 2.5: Lemma and and bamboo have three stamens) . Wheat stamens palea are small and produce about 1000-4000 pollen grains per anther. Wheat pollen is shed in this three-celled condition. The unilocular carpel of wheat, like in other grasses, has one ovule. Figure 2.6: Androecium and Gynoecium

Lodicules:

There are two delicate ovate lodicules present at the base of ovary. These are considered to be modified perianth structures. They absorb water and swell. Swelling of lodicules leads to flower opening and anthesis. Size of lodicules is also variable

45

among genotypes. Cleistogamous chasmogamous flowers.

genotypes

have

smaller

lodicules

than

Anthesis and Mode of Pollination: (Fig. 2.7) Wheat normally is self-pollinated crop. Chasmogamy is quite common. Cleistogamy is also observed in a few genotypes. Anther extrusion is also variable, cleistogamy to complete extrusion. In adverse climatic conditions, when the anthers fail to dehisce, crosspollination may occur, depending on availability of air borne pollen. Cross pollination ranges from 0.5 - 1.0 per cent, as most of the pollen is shed before the anther comes out of the glumes (chasmogamy). In other situations, the filament may not elongate at all and the pollen is deposited in the florets resulting in cleistogamy. The main tiller flowers first and the lateral tillers later in the order of their formation. Blooming is also in the same order. Flowering begins in the upper part (2/3 rd from the base) of the spike and proceeds in both the directions (see PowerPoint presentation). The glumes normally open during the flowering process, the anthers protrude from the glumes and part of it is shed outside the flowers. Florets at anthesis are forced open by the swelling of the lodicules. Filaments elongate very rapidly, attaining three times their original length in about 3 minutes. The stamens thus help anthesis by quickly exerting and Figure 2.7: Anthesis exposing the anthers. Pollen is short lived and remains (see white anthers) viable for only 15 to 30 minutes. Stigmas remain receptive for 4 to 5 days and may prolong to 13 days depending upon the environment. This short viability of pollen is characteristic of the plants in which pollen is released at three-nucleate stage. Fruit (Fig. 2.8) A wheat grain is a small, dry, indehiscent, one-seeded fruit with a thin pericarp and is called as a caryopsis. The shape of the grain can be ovate, elliptical or oval. The 46

surface of the wheat grain is smooth except at the stigmatic end where there is a tuft of persistent hairs known as the brush. The colour of the grains varies from red (reddish brown) to white or amber. Emasculation and Pollination Emasculation: (Fig. 2.9) Crossing in wheat is simple but time consuming and Figure 2.8: Wheat grains laborious. Since the flower is bisexual, it is necessary to emasculate or remove the anthers from the spike that has to be pollinated. The flower maturity starts from the middle of the spike and extends in both directions i.e. it follows the pattern of flowering. There can be a difference of 1-2 days in maturity between the middle and the extreme (upper and lower) spikelets. Hence, depending on the condition of the spike, one or two spikelets from either side and the terminal spikelet are removed before emasculation. Within each spikelet, the two lateral ones are bigger and the inner ones are smaller and also mature later. The spike which Figure 2.9: Emasculation : (a) Removal has to be crossed is selected at a stage of central floret (b) emasculated spike when the lower portion of spike is still inside the flag leaf. At this stage the anthers of the middle spikelets are fully grown and still green, indicating that they will ripen in a day or two. The central florets are removed by holding them with a forceps and pulling them downward and outward . This leaves only the outermost florets of each spikelet. The awns are cut slightly below the glumes which helps in the removal of anthers. After emasculation the ear is normally covered with a butterpaper bag to prevent natural pollination. Pollination (Fig. 2.10, 2.11) Pollination is effected by placing a freshly opened anther into the emasculated floret or dusting pollen. After pollination, the bag is again kept on the pollinated spike to avoid any foreign pollen. The bag may be removed after a few days, or kept till maturity.

47

Male parent spike is removed from the plant and the spikelets are cut from ½ from the top without damaging the anthers. This spike is then exposed to the sunlight during morning hours (8.00AM-9.00AM) to release the pollen grains. Stamens elongate very fast and come out of the spikelets. These spikes are gently taken to female (emasculated) parents and inverted inside the bag covering the emasculated spike. Spikes are shaken and are enclosed along with the emasculated spikes to achieve maximum pollination and thus fertilization. To perform large number of crosses, a slightly modified method, called the “twirl method” has been developed. In this method, the spike that has to be used as female is emasculated as in the previous case, but the glumes are cut Figure 2.10: (a) Male spikes deeper, so that the stigma is slightly exposed. inserted in the soil near the For pollination, a spike is selected which is female parent in the sun light to ready to dehisce pollen grains. This can be release the pollen grains by (b) easily judged by inspecting a few florets of a protruding the anthers spike and selecting those which have yellowcoloured anthers. The awns are cut and the spike is kept erect in sun for sometime to allow the filaments to elongate and the anthers to dehisce. At an appropriate stage the spike is inverted carefully and rotated around the previously emasculated spike while still in the glassine bag. The pollen grains are thus deposited on the stigmatic surface. This avoids the tedious procedure of placing anthers or pollen manually in each of the florets. In both cases, a label is kept inside the bag and one is kept outside the bag tied to the Figure 2.11 : (a) bagging after peduncle. Details like the female and male selfing and (b) bagging after parents used in the cross, date of pollination etc. are mentioned on this label.

48

Floral Biology of Rice

Family: Gramineae English name: Rice Common name: Dhan (in Hindi), bhatta (in Kannada), arisi (in Tamil) etc. Genus: Oryza Species: sativa Chromosome No.: 2n=24 Rice is a staple food of more than 60% of the world’s population. Maximum area under rice is in Asia. Among rice growing countries, India has the largest area of about 40.2 million-hectare followed by China and Bangladesh. Inflorescence Rice Panicle

49

The inflorescence of rice is a terminal panicle, 7.5-38.0 cm long with single flowered spikelets. High day temperature, high solar radiation and low night temperature promote panicle production. More panicle would mean a greater number of available spikelets.

PART OF THE RICE PANICLE SHOWING ITS BRANCHING PATTERN AND ATTACHMENT OF SPIKELETS

Tertiary branch

Spikelets

Secondary branch

Main axis Spikelets: The spikelets are single-flowered, each with a short stalk. Glumes: There are two small glumes at the base of each spikelet. Floret: The floret consists of the lemma, the palea, two lodicules, the androecium and the gynoecium. Lemma: The lemma is large and hairy. It is awned 5-nerved structure. Palea: The palea is hairy, smaller than the lemma and is present opposite to it. It is three-nerved structure. After maturity, the lemma, the palea and the glumes remain attached on the seed as a cover called husk. Flower: The flower is bisexual, zygomorphic and bracteate.

50

Perianth: The two-minute scales like structures present at the base of florets are called the lodicules. They are thick and fleshy. Androecium: The androecium consists of six stamens arranged in two whorls whose filaments are short in earlier stage. About 6 day before heading, the pollen grains mature and the flag leaf sheath swells, which is an indication of booting stage. The filament elongates immediately after floret opening and brings anther to the level of stigma. The total number of pollen grains per anther is reported to be directly correlated with anther size which generally varies from 0.9 to 5.4mm The number of pollen grains per anther (Y) with known anther length (X) is estimated

SPIKELET OF RICE

by the formula Y= -1172+1277X, but this relation does not hold true when temperature becomes lower than 200C. Normally 2-3 pollen grains are required per stigma to fertilize one egg cell.

51

DIAGRAMATIC PRESENTATION OF SPIKE OF RICE Gynoecium: The gynoecium is monocarpellary and has a superior ovary, with two feathery stigmas on a style. Receptivity of stigma is maximum during the first 3 days after opening of spikelet and then is gradually lost after 7 days. Stigma exertion, large stigmatic area and its receptivity, all play a major role in determining high seed set in CMS parent.

Anthesis and Mode of Pollination Rice is a self-pollinated crop, with 0.1 to 4 per cent outcrossing. The flower may open from 7 a.m. to 4 p.m., depending upon the season. Most of the flowers start opening

52

at the apex and the flowering proceed downward in the panicle, but in the branches, it is not strictly so. In rice three types of pollination are possible: • The usual process is that the anther burst as they emerge and pollinate the stigma (leading to selfpollination). • The anthers burst open and pollination takes place before blossoming, generally at high temperature and under low humidity (leading to selfpollination). • Under certain temperature and humidity conditions, the anthers may emerge from the flower without bursting and such flower is generally cross pollinated. The terminal spikelet opens first and

then the lower ones. The stigma remains receptive from the time of anthesis up to 3 days. Pollen grain on the stigma germinates in about three minutes after the pollination. The ovary with single ovule develops into the fruit / caryopsis. Emasculation Several methods have been used for emasculating rice: (a) Standard method: This is most widely used method of emasculation in rice.

53

(b)

Remove all the immature and mature spikelets from the panicle. The mature spikelets are translucent and have anther outside the florets. Separate the glumes with the help of a pair of forceps and gently remove all the six stamens. To speed up the emasculation, suction may be used. For this, a pipette is attached to a vacuum pump and the tip of pipette is inserted in to the florets to collect the anthers. Emasculation is generally performed in the evening and the pollination is done next morning. After emasculation, cover the female with butter paper bags. Tagging is also done. Hot water treatment: This method of emasculation is commonly used in Japan. The immature spikelets are cut off. The panicles are dipped in hot water containing constant temperature of 43 0C for at least 5 min. Great care should be taken to have constant temperature of water for which thermos flasks are best. This method is relatively more time consuming and pollen must be immediately available to introduce in to the florets before their closing.

Pollination Collect the pollens just before anther dehiscence. To apply CARYOPSIS OF RICE pollens, remove butter paper bags and the anthers from the derived male parents are shaken over the emasculated florets. If pollens are not available in plenty then repeat the above process. If two panicles on the same plant are to be pollinated by the same male parent, they are brought together by wrapping the two clums and are tied with a clip. The other bag is also placed over both panicles.

54

Floral Biology of Oats Family : Genus : Species: Chromosome No.: Basic chromosome No.:

Gramineae Avena sativa 2n = 42 x =7

Ploidy nature: Oats forms a polyploid series of Diploids, Tetraploids, and Hexaploids. The genus has been classified into 19 texonomic species of which ¾ Ten are Diploid (2n = 14) ¾ Five are tetraploid (2n = 28) ¾ And four are Hexaploids (2n = 42) Other Species: ¾ fatua ¾ sterilis L. (Wild varieties of oats)

Terminal spikelet

spikelets

Oats rates fourth among our cereal grains after wheat, rice and maize. Oats originated as a wild grass and had been greatly altered by centuries of cultivation. The grain was Fig.5.1.Panicle of oats first known as a weed among other cereals. The oldest oat grains known were found in Egypt in materials dating to the twelfth dynasty. Oats are mainly grown as fodder crop. Oat growing countries are Canada, Germany, France, Poland, England, Wales, Sweden, Denmark, Argentina, Russia and India. Varieties of A. sativa occupy the major oatproducing area of North America, Northern Europe and Asia and all leading oat

55

Single terminal spikelet

Node

Rachis

Fig.5.2

producing countries produce largely exclusively oats of this type. Cultivation of this crop in India can certainly be traced to the beginning 19th century.

Inflorescences: Inflorescences of the oat plant is a panicle (Fig. 5.1, 5.2) composed of a central loose, open rachis with five to seven nodes, from which branches arise bearing spikelets. Each lateral branch terminates in a 56

Fig.5.3

single apical spikelet. Other spikelets are born on second or third-order of branches. Each panicle may have 20 to 50 spikelets. Spikelets consist of several florets enclosed in two-empty glumes, with the tip of one glumes extending slightly above the other. Florets with in each spikelet are arranged alternatively upon a central axis, the rachilla, and usually the two

57

Fig.5.4

basal florets are fertile. The flowers are perfect zygomorphic, bracteate and hypogynous. The flower consists of a lemma and a palea, two lodicules, three stamens and one pistil (Fig. 5.3, 5.4, 5.5). Spikelets:- Three to four florets are present in each spikelet, but the third or fourth floret is sterile. Two glumes cover these florets (Fig. 5.3, 5.4, 5.5). Glumes: - The two outer bracts of the spikelet. They are broadly lanceolate, pointed, boat shaped, usually glabrous and arched. The glumes may be pale, yellow or red (Fig. 5.3, 5.4, 5.5).

Fig.5.5

Lemma:- Lemma is a rigid structure which encloses the rachilla at the base of the flower. Its primary function is to

58

protect the caryopsis. Lemma varies in colour from white, yellow, gray or red to black. It may be awned or awnless. Palea:- One membranous palea is present opposite to lemma. Primary function of palea is to protect the caryopsis (Fig. 5.3, 5.4, 5.5). Lodicules: - Two small, smooth, pointed and shinning lodicules are present at the base inside the floret; mature lodicules are thick at the base and pointed at the tip. The action of the lodicules in opening the flowering glumes is not so important in self fertilized plants, but enhance cross-pollination by wider opening of the florets.

Fig.5.6

Androecium: There are three stamens present. Stamens first appear as papillae upon the apex of the floral axis above the flowering glumes primordia. The versatile anther consists of four locules. The filament is attached to the central axis at its lower extremity (Fig. 5.3, 5.4, 5.5). Gynoecium: - (Fig. 5.6). There is one ovary with bifid stigma. The ovary is elliptical in cross section. Long monocellular, epidermal hairs entirely cover the ovary and also present on the interior surface and base of styles. The tip of style and the inner surface near to the base are covered with stigmatic branches. A single, sessile, anatropous ovule is located inside the ovary.

Fig.5.7

Anthesis and mode of pollination: -The stigma becomes receptive one day before anthesis and remains receptive for five days. The receptivity of the stigma depends upon genotype and the environmental conditions. Anthers dehisce the pollens just before or during opening of the floret. As the grain matures, the lemma and palea remain attached to the kernel forming the hull except in the naked or hulless oat. The

59

hull comprises 25-30 per cent of the total weight of the grain. At anthesis the stigma elongates, the anthers dehisce and become introse and elongated, the floret opens and anthers are exerted from the floret. Self-pollination is the rule but cross-pollination may range from 0.5-1.0 per cent. Emasculation: - (Fig. 5.8). Since anthesis normally occurs in the afternoon, emasculation should be done in late fore noon or early afternoon. Select those spikelets from a panicle in which anthesis is expected one or two day after emasculation. Keep only one floret within a spikelet. By applying light pressure on the dorsal glumes. Separate glumes, palea and lemma and remove all the three anthers with the forceps. When emasculation in delayed until very shortly before the time of normal anthesis, the floral Anthers structure, being better developed will likely to be less injured by emasculation operation than they would be if manipulated a day or more before pollination. Cover the emasculated floret with a proper (e.g., Forceps glassine) bag to prevent contamination from foreign pollen and tagging is done. Fig.5.8. Emasculation in Oats Pollination: - Researchers have reported different time interval for pollinating the Three emasculated floret: anthers • First view: Pollination should be done within 1-3 days of emasculation. • Second view: Emasculate the floret in the morning and pollinate in the evening. Method 1: Anthers from desired male parent are collected. The anthers are yellow and plump. Separate the lemma and palea of emasculated floret using forceps and place the collected anthers (with the help of forceps) in the inner side of the lemma. Cover the pollinated floret with the same glassine bag used in emasculation.

60

Placing anthers inside the emasculated floret (pollination) Fig.5.9. Pollination in Oats Method 2: Approach method of pollination is also used in oats. In approach method remove secondary floret and the anthers of the primary floret. The upper portion of each spikelet after emasculation is removed by clipping glumes, lemma and palea just above the stigma. The pollens from the male parent are shed directly on the stigma of erect clipped spikelets.

61

Floral Biology of Pearl Millet Local name:

Pearl-Millet (Bajra)

Family: Genus: Species:

Gramineae Pennisetum americanum (L) K. Schum glaucum (L) R.Br (most acceptable) typhoides 2n = 2x = 14 P. purpureum Africa

Chromosome Number: Related Species: Origin:

Fig. 6.2 Plant

Pearl millet is the fourth most extensively cultivated cereal in India. It is termed as poor mans’ crop because it has high Fig. 6.1. nutritional value Spike and can successfully be grown on marginal lands and can tolerate drought and heat to a great extent. Its grain is generally superior to sorghum as human food and approximately similar to maize as feed grain (Fig. 6.2). The inflorescence is a cylindrical spike tapering towards the ends and may vary in length from a few centimeters to over a 62

Fig. 6.3. Panicle initiation stage

meter. It consists of a central rachis with closely spaced fascicles(Fig. 6.2, 6.7).. Each fascicle contains one or more spikelets (generally 2-5, The most common number being two) and a whorl of bristle (usually 30 to 40 in number). However, there are generally two spikelets in most of the fascicles. The bristles are the prolongations of the fascicles and may be longer or shorter than the Fig. 6.4. Ear Emergence spikelet. (Fig. 6.6, 6.7, 6.8).

63

Each spikelet comprises a short lower glume and two florets, the lower one being staminate or some times even without stamens, and upper one bisexual or perfect. The male floret consists of a single lemma enclosing three stamens, but has neither palea nor lodicules. The perfect floret has a broad lemma, a thin palea, three stamens and carpel with two styles which terminate in a brush-like stigma (Fig. 6.8, 6.10).. Anthesis: (Fig. 6.5).

Fig. 6.5

The stigmas begin to appear two to three days after emergence of the spike. Stigma attains full length after 36 to 48 hours and remains Fig. 6.6 receptive for one to two days. The anthers emerge after stigmas dry up. The anthers of the bisexual flowers appear two to three days before those of the staminate flowers. Style divides in two branches in its upper part and possesses stigmatic hairs to admit pollen grains. Stigma takes 12 to 24 hours to protrude and open out, and remains receptive for one to two days. 64

Mode of pollination: Pearl millet is a highly cross pollinated crop and up to 80 per cent out crossing

Fig. 6.7 occurs in it. The emergence of anthers is slow probably because of the absence of

Fig. 6.8 lodicules. Emasculation:

65

Emasculation is not required in pearl millet due to its protogynous nature (Fig. 6.9) The head is covered with glassine bag before style appears. The exerted style can be watched through the glassine bag. When styles are exerted then pollination is performed with desired male parent. However, the emergence of the stigmas before emergence of the anthers is used for artificial cross-pollination. Pollination Pearl millet is highly crosspollinated crop. About 80% of the flowers are cross

Fig. 6.9

Fig. 6.10. Spikelets, florets and stamens of pearl millet

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pollinated. However, about 20% of selfing occurs especially in the lower part of the ear. Self Pollination 1. Bag the spikes before the emergence of stigma. 2. Length of bag must be such that lower most spikelets, which will be emerging later, could be covered. Usually parchment or khaki paper bags of 5cm x 60cm (depending upon the length of spike achieved in that genotype) are used. 3. Alternate way is that two spikes from the same plant may be enclosed within the same bag. These spikes are such that the older one sheds Pollen when the stigma emerges in the second spike.

Fig. 6.11

4. Label it with lead pencil. Cross-Pollination 1.

Minute flower size and protogynous condition of flowers makes emasculation and crossing difficult and laborious.

2.

An easy method of crossing without the necessity of emasculation takes the advantage of protogynous condition of bajra.

3.

Being sure that anthers of a spike will not ripen at the time of stigma receptivity we can select a spike

4.

About four-fifth of the upper spikelets of the inflorescence are removed. The remaining spike of spikelets is enclosed in a bag before the stigma emergence. Upper spikelets bloom a day prior to lower spikelets.

5.

Bag the spikes to be used as pollen parents and collect the shedding pollen dust.

6.

In the morning dust the pollen grains on the stigmas.

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7.

Bag the spike after gross pollination has taken place.

8.

Label the necessary information.

Fig. 6.12 Other methods include: 9.

Use of male sterility: Male sterility (CGMS) may be incorporated for genetic emasculation of bajra: The male sterility conditioned by recessive genes is introduced in to plants to be used as females by back crossing and the genetic emasculation is completed.

10. Hot water treatment: Dip the spike in hot water having a desired temperature of 45-50oC for 1 to 10 minutes depending up on the variety. Seed production (Fig. 6.11, 6.12, 6.13). Pearl-millet, being a cross-fertilized crop, has been improved through conventional breeding procedures by developing composites, synthetics and hybrids. Before the exploitation of cytoplasmic genetic male sterility (CMS) in 1965, pearl-millet varieties were used to be open-pollinated. But after 1965, the development of first ever hybrid ‘HB1’ by using CMS resulted in a break through in the yield levels of this so called poor man’s crop. Subsequently, more hybrids and synthetics with great yield potentials and having resistance to various diseases

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were developed. To maintain the high yield levels of released cultivars and to minimize the chances of varietal deterioration, it is essential to adopt proper seed production practices. The genetic purity of the varieties must be maintained. Production of Hybrid seed using CGMS: (Fig. 6.13: Example of HHB-67) Almost all the varieties of pearl millet are the hybrid varieties. The hybrid pearl-

Fig. 6.13

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millet seed is produced by utilizing cytoplasmic genetic male sterility. The various steps involved in the production of hybrid pearl-millet seed are: maintenance of parental lines namely: 1. Male sterile lines (A-lines). 2. Maintainer lines (B-lines). 3. Restorer lines (R-lines). The maintenance of parental lines is referred to as foundation seed production, whereas the hybrid seed production is known as certified seed production. Production of Breeder Seed Breeder seed’s the seed of the highest genetic purity and is produced under the direct supervision of breeder, originating institution or agency. It is the source for the production of foundation and certified class of seed. Breeder seed of maintainer (Line B) and restorer (Line R) is produced by growing them in isolated plots having a minimum distance of 1000m from fields of other varieties or some varieties not conforming to varietal purity requirements for certification. The breeder seed of established pearl-millet variety can be maintained by raising breeder seed of a variety in isolation (more than 1 km) through mass selection. The seed plot in isolation is thoroughly rouged at various stages such as vegetative, flowering and maturity, and all off-types are removed and when noticed. The breeder seed of pearl-millet variety is often purified by mass selection. Approximately 2000 to 3000 true to type plants are selected at maturity, harvested separately, and after careful sorting bulked to constitute the breeder seed. Modified mass selection by dividing the plot in sectors and selecting an equal number of true to type plants from each sector can also be practiced for maintaining breeder seed. Maintenance of Male sterile lines: The male sterility in pearl-millet is due to cytoplasmic genetic factors (CGMS). It is maintained by crossing male sterile line (Line A) with a male fertile, non-pollen restoring maintainer (Line B) in an isolated plot. This B line is a sister strain of line A and is essentially similar to line A in genetic constitution except that it carries fertile pollen (Isogenic/isonuclear line). In a crossing field, the usual planting ratio of line A and Line B is 4:2. In addition 4-8 border rows are planted with line B around the field. The seed harvested from line A would be male sterile and is used for hybrid seed production. The field for producing the foundation seed of male sterile line A must be isolated by 1000 m (1 km) from other pearl-millet fields.

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Maintenance of maintainer line: The seed of maintainer line is produced by sowing B lines in isolated plot or B lines sown in the field for production of A-seed can be harvested separately to get B-seed. Maintenance of restorer line: The seeds of restorer line (Line R) are produced by multiplying the seed in an isolated plot having a distance of 1,000 m from nearby pearl-millet fields having different cultivars or from the same restorer line not conforming to certification standards. Hybrid seed of pearl-millet The hybrid seed is produced by crossing male sterile line (Line A) with a specific restorer line (Line R) in an isolated plot. Since hybrid seed is a commercial produce and is termed as certified seed, the requirements for isolation distance are 200 m from fields of other varieties and 25 m from fields of the same variety not conforming to varietal purity requirements for certification. The hybrid seed is produced by growing 6 rows of male sterile line A alternated by 2 rows of restorer line (Line R). The 2:6 proportion of male rows (Line R) and female rows (Line A) can be increased safely to 2:10 depending upon the pollinating vigour of the restorer parent. The seed harvested from the female rows (A-lines) is the hybrid seed.

PEARL MILLET FLORAL BIOLOGY ¾ Inflorescence is a one half to more than three feet long cylindrical terminal spike consisting of a central rachis on which infinite numbers of fasicles are packed. ¾ A fascicle contains one or more spikelets and a whorl of bristles. It is considered to be unit of inflorescence. ¾ Spikelets occur in pairs. ¾ Each spikelet contains two florets partially Fig. 6.14 enclosed by a short 71

¾ ¾ ¾ ¾ ¾

¾

¾

¾ ¾

outer glume and another inner glume. Lower floret is staminate and upper one is hermaphrodite. Three stamens are present with filiform filaments and versatile anthers in each floret. Style develops into two branches (bifid feathery stigma) in its upper part and possesses stigmatic hairs to admit pollen grains. It is protogynous in nature. Fig. 6.15. Stigma Three flushes of anthesis occurs emergence in pearl millet (Fig. 6.5).. First Flush of anthesis: Emergence of stigmas start from top to bottom. Stigma takes 12 to 24 hours to protrude and open out, and remains receptive for one day (Fig. 6.9, 6.15).. Second Flush of anthesis: Before the basal stigmas protrude, stamens of perfect florets also start emerging from tip down wards. Third Flush of anthesis: Before the emergence of stamens of hermaphrodite florets reach the base, the second flush of emergence of anthers from staminate flowers start from the tip down wards. Humidity and cool temperatures favour anthesis. The maximum emergence of styles is between 9.00a.m. and 3.00 p.m. The maximum number of stamens comes out between 12.00 p.m. and 2.00 a.m. and maximum between 3.00 p.m. and 6.00 p.m.

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VARIATION FOR FLORAL CHARACTERS IN PEARL MILLET Fig. 6.16.

Fig. 6.17.

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Fig. 6.18.

Fig. 6.19.

Fig. 6.20.

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Floral Biology of Maize Family: Poaceae (Gramineae) Botanical Name: Zea mays L. Chromosomes Number: 2n =20 Fig. 7.1

Corn, commonly known as maize (Zea mays L.), (Fig. 7.1) belongs to family Poaceae (Gramineae). Its close relatives are Euchlaena and Tripsacum and these three are easily crossable with each other. Maize, rice and wheat are the three main cereal crops of the world. Unlike rice and wheat, maize is consumed as feed for livestock rather than directly as food. Maize is basically grown as an energy crop. It is consumed directly by majority of people. Maize is also used for protein, oil and Tassel is a good source of starch. silk In some parts of Latin America, it is grown for human consumption. Agro botanical studies indicated Mexico and/or Cobs low land Central America as the centre of variability for the commercial dent types. FLORAL BIOLOGY Fig. 7.2

Maize plant (Fig. 7.2) is monoecious. The male or staminate flowers are found, on the terminal

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inflorescence known as tassel (Fig. 7.2, 7.5 and 7.6), whereas female flowers are on the lateral branches called ear shoots (cobs). The tassel comprising male flower is present on the top of the plant in which central axis is in continuation of the main axis of the stalk. Primary, secondary and tertiary branches are also present in a tassel. The spikelets are present in pairs, one being sessile and other being pedicellated (Fig. 7.4 and Fig. 7.5). Paired spikelets are arranged in several rows on the main axis and in two rows on the lateral branches (Fig. 7.6). These spikelets are similar in structure, one is borne on a short pedicel and other is sessile. Each spikelet consists of a pair of glumes that comprises of two florets, each of which is enclosed by a lemma and palea and has two lodicules, three stamens and rudimentary pistil. The ovary ends in a thread like structure, the silk which is actually modified style. Silk length may attain 45 cm in some varieties. Each floret contains there anthers (Fig. 7.4 and 7.5) and each anther produces about 2500 pollen grains The pollen grains are very small, barely visible to the naked eye, light in weight, and easily carried by wind. Pollen is dispersed by wind; however, insects cause an insignificant amount of pollen dispersal. The amount of pollen dispersed from one tassel varies from genotype to genotype. Hybrids shed more pollen than inbreds. Dispersal of pollen may begin about 3 hours after sunrise and continue for 1 to 3 hours. However, the dispersal may be delayed until mid day. The pollen remains viable for few minutes because of rapid Fig. 7.3 desiccation Silk become receptive as soon immediately after emerging from the ear husk. It may require up to 5 to 6 days for all silks to emerge from an ear. Receptivity up to 14 days after emergence has been reported. The female inflorescence consisting of pistillate flowers is located in lateral side of the main stem. The single inflorescence comprises many vertical rows of densely crowded female flowers on the fleshy rachis. The sessile spikelets are present in pair on a rachis. Due to this, each cob contains even number of kernel rows. Within each spikelet, two flowers are present. The lower flower is reduced to form lemma and palea. Rudimentary lodicules may also be present. The pistil is tricarpellary, out of which two carples extend to form silk and third forms ovule, the silk is the modification of style. 76

Fig. 7.4 - FLORAL PARTS OF MAIZE (PHOTOGRAPHS)

77

Silk

Pollen

anthers

Sessile spikelet Spathe

Cob

Tassel

FEMALE INFLORESCENCE

Pedicillate spikelet

MALE INFLORESCENCE

Paired Spikelets

Fig. 7.5 Stamen Silk

Lemma Pedicillate

Paired spikelets

Sessile

Lodicules

Floral Diagram

Glume II

Glume I

Spadix

AN OPENED SPIKELET

Spathe

FLORAL PARTS OF MAIZE (Zea mays)-DIAGRAMS The desiccation of pollen grain occurs quickly because of this outer membrane, which results in the loss of pollen viability within a short period. The stigma (silk) becomes receptive as soon as it emerges from the stalk and may remain receptive up to 14 days after emergence depending upon environment. Maize is generally protandrous, that is, the male spikelets mature earlier than the female spikelets. Because of monoecious plant habit and protandrous nature of anthers, the maize is considered highly cross-pollinated crop. The pollen is generally dispersed by wind. The wind-borne nature of the pollen, monoecious plant type and

78

Fig. 7.6

Tip of tassel

Tassel at anthesis

Pair of spikelets

TASSEL (PART OF) AT VARIOUS STAGES protandry enhances cross-pollination, but there may also be about 5 per cent selfpollination. SELFING AND CROSSING TECHNIQUES Selfing • •

At the time of flowering, right plant must be selected to cover the ear shoot. Ensure the stage of cob is such that the silk emerges after one or two days.

79

• • •

• •

Short bags are placed over each ear shoot. Tassel of the same plant is also covered with tassel bag (craft paper of size 7.5 cm x 16 cm) for the collection of the pollen. Check the ear shoot daily. If it is at the right stage, then in the morning hours the tassel bag of the same plant is lifted and dusted on the cob. Bag the spadix with tassel bag and repeat the process in the next morning. Put the tag and label it.

Crossing • •

•

• • •

•

Fig. 7.7 A tassel produces its utmost quantity of pollen in the second and third days of dehiscence. The tassel bag is placed over the tassel of the male parent on the day before the pollination to avoid from contamination of foreign pollen. The bag is tied by a paper clip or a staple. When the ear shoot is at the right stage of the female parent and the tassel of the male parent also has abundance of pollen grains, the tassel bag is lifted and dusted on the ear shoot and the ear shoot bag is replaced by the same tassel bag to supply maximum amount of male parent pollen grains. The bag should again be fastened by paper clip. The tassel bag should remain over the ear shoot until harvest. When more than one ear on a plant is pollinated, seed set on the lowest ear is most reliable, if pollinated one day before the ear at higher node. Lower ear has least chances of contamination. Fig. 7.8 Label the tassel bag with graphite pencil properly indicating male parent, date of pollination etc.

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Floral Biology of Sorghum Family: Gramineae (Poaceae) Genus:Sorghum Species: bicolor (L.) Moench Chromosome No.: 2n=20 Common names : Sorghum (Eng.) Jowar (India), graansorghum (Afr); mabele (Pedi, Sotho, Ndebele); amabele (Z) amazimba (Xhosa). Other names : Durra, Egyptian Millet, Feterita, Guinea Corn, Jowar, Juwar, kaffir corn, Milo, Shallu and Sudan Grass.

Fig. 8.1. Sorghum Crop The grass family (Poaceae) is a large family of 10,000 species and at least 600 genera. Grasses range in size from small annuals (Poa annua) to towering, timber bamboo (Dendrocalamus giganteus). This is unquestionably the most important plant family, providing the majority of food for humans and their domesticated animals. The grasses are relatively recent additions to the earth's flora, having evolved only 30 to 40 million years ago, long after the demise of the dinosaurs. Vast grasslands provided food for the rising age of herbivorous mammals which in turn provided the food for a variety of carnivores. In addition to cereal grains (rice, wheat, barley, oats and corn), grasses are the source of bamboo shoots used in

81

Asian foods, the primary source of sugar (sucrose) from sugar cane (Saccharum officinarum), alcoholic beverages from barley malt (beer) and fermented rice (sake), and bamboo timbers for construction and scaffolding. Sorghum (Fig. 8.1) is forth in importance among the world's cereals, coming after wheat rice and maize. It grows in the tropics and subtropics. In India it is known as Jowar. Height generally varies from 40-600 cm (Fig. 8.2). It's stem has 7-18 nodes and internodes. Sorghum is grown in three seasons: 1. Kharif season during monsoon i.e. from June-July to September. 2. Winter season i.e. from September to February it is 35% of the total sorghum hectarage at national level. 3. Summer sorghum planted from February to June under irrigation.

Fig. 8.2. Sorghum Plant

It is used for human consumption as food in African countries. It is also used as animal feed; it can be used green as well as dried (straw). It is rich in starch (7080%) and proteins (9-13.5%). It contains 2-3% cellulose, 2-2.5% minerals and 2.53.5% fats. Sorghum is a genus of about 30 species of grasses raised for grain, native to tropical and subtropical regions of Eastern Africa, with one species native to Mexico. The plant is cultivated in Southern Europe, Central America and Southern Asia. Most cultivars are annuals, few are perennials. Species • Sorghum almum • Sorghum amplum • Sorghum angustum • Sorghum arundinaceum • Sorghum bicolor (L.) Moench • Sorghum brachypodum • Sorghum bulbosum • Sorghum burmahicum • Sorghum controversum

• • • • • • • • •

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Sorghum drummondii Sorghum ecarinatum Sorghum exstans Sorghum grande Sorghum halepense Sorghum interjectum Sorghum intrans Sorghum laxiflorum Sorghum leiocladum

• • • • • • • • • • • •

Sorghum macrospermum Sorghum matarankense Sorghum miliaceum Sorghum nitidum Sorghum plumosum Sorghum propinquum Sorghum purpureosericeum Sorghum stipoideum Sorghum timorense Sorghum trichocladum Sorghum versicolor Sorghum virgatum

SORGHUM INFLORESCENCE / ARROWS

Compact

Inflorescence

Fig. 8.3

The inflorescence (Fig. 8.2 and 8.3) is a panicle (called arrow) with a central rachis from which primary branches arise. They give rise to secondary and some times tertiary branches which carry the racemes of spikelets. Panicle: A panicle may be shoot, compact or loose and open, 4 to 25 cm or more in length (Fig. 8.3). The central axis of panicle the rachis may be striated and it may be hairy or glabrous. The panicle usually grows erect at the apex of the clum, but may be recurved. It releases 25-100 million pollen grains.

Lose

Raceme: A raceme always consists of one or several spikelet. One spikelet is always sessile and the other pedicellate (Fig. 8.4), except the terminal At maturity At anthesis sessile spikelet, which is accompanied by two pediceled spikelets. Raceme may vary in length according to number of nodes and length of

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internodes. On the pedicellated spikelet, the pedicels vary in length from 0.5 to 3.0 mm and usually similar to internodes.

Fig. 8.4

Flower: Perfect flower (Fig. 8.7, 8.9) consist of two glumes one hairy lemma, a small palea, small awn, 3 stamens two lodicules and one pistil. Ovary has two styles with feathery stigmas. Mode of Pollination: Sorghum is an often cross pollinated crop like pigeonpea and cotton. The extent of out crossing ranges from 4-20 per cent on account of the exposure of the stigma before the dehiscence of the anthers. Anthesis (Fig. 8.5 and 8.6): The sorghum inflorescence usually begins to flower when the peduncle has completed elongation. The first flower to open is either the terminal or the second flower of the uppermost panicle branch. The time at which flowering commences has been reported are as follows: Timing

Anthesis (Event)

2.30 a.m.

Glumes begins to open

2.31 a.m.

Staminal column visible

2.32 a.m.

Stamens separate

2.33 a.m.

First anther tilts down and becomes pendent

2.34 a.m.

Other two another tilt down and become pendent

2.50 a.m.

Glumes begin to close

3.15 a.m.

Glumes completely closed

Emasculation: Various methods of emasculation in sorghum are described below:

84

Fig. 8.5

Fig. 8.7

Fig. 8.6

85

Fig. 8.8

Hand Emasculation or traditional methods: Remove all the open spikelets with fine blade scissors preferably in the after noon. Remove all the three stamens with the help of forceps. Care must be taken that there is no injury to stigma. Hot water treatment: The immature and mature spikelets are removed from the panicles which have just begun to gloom. The panicle is then inserted in a sleeve of rubber, which tied lightly around the panicle and open at the top. The panicle is inserted for about 10 min. in 480C hot water. After treatment cover the panicle with bag. Male Sterility: Genetic (GMS) and cytogenetic male sterlity (CMS) are available in sorghum. These types of male sterlity may be used for the production of hybrid seed on a large scale. Tagging is done as usual. MSCK 60 (male sterile combine Kafir 60) is a male sterile variety of sorghum. It contains the Kafir chromosomes and Milo cytoplasm.

86

87

VARIABILITY FOR GRAIN COLOR AND EAR (ARROW) SHAPE IN SORGHUM

One phenomenon which has been observed by the seed producer is the occurrence of female sterility in male sterile parent resulting in poor seed set. Mainly observed in K 60A, 2071 A and 2219 A verities. Pollination: For pollination the emasculated panicle the pollen is collected in the morning from the desired male parent panicle which is flowering. Fig. 8.9 Dust the pollen on the emasculated spikelet and cover is again with pollinated bag. Fruit (Fig. 8.9): Fruit of sorghum is caryopsis (Kernel), naked or covered. The individual grains are small- about 3-4 mm in diameter. They vary in colour from pale yellow through reddish brown to dark brown depending on the cultivar

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Floral Biology of Sugarcane Class Order Family Group Genus Species

: : : :

Monocotyledones Glumaceae :Gramineare Andropogneae Sacchrum officinarum sinense Cultivated barberi robustum Wild spontaneum

Chromosome Number Sacchrum officnarum S. barberi S. sinense S. spontaneum S. robustum

Sugarcane crop

2n = 80 2n = 90, 92 2n = 116, 118 2n = 40 to 128 2n = 60 to 148

Ploidy Nature Sacchrum species are extremely complex polyploids, The most common basic chromosome numbers are 8 and 10 Sacchrum officinarum; Octaploid , x = 10 S. spontaneum; Two groups Îx=8 2n = 40, 48, 52------Î x = 10 2n = 40, 50, 60------S. robustum; x = 10

2n = 60, 80.

Sugarcane is important commerical crop used for large scale production of sugar in the world. Out of about 93.05 million tonnes of sugar produced in the world during 1977-78, about 55 million tonnes is reported to be from sugarcane. 89

Sugarcane provide the cheapest form of energy giving food (sucrose) with the 90

lowest unit of land area per unit energy produced. Average man’s annual consumption of energy is 1 million calories which is produced by one-eight of an acre of sugarcane while wheat flour requires 7 times, milk 20 times and beef over 100 times. Flower Structure Inflorescence The inflorescence consists of an open branched panicle known as the arrow and may contain thousand of florets. The loose terminal panicle is silky due to rings of long hairs below each spikelet. At the base of panicle, primary branches are about 15cm long. The secondary branches tend to arise in two rows alternately along the primary branches and may contain tertiary branches. The spikelet consists of two florets, one sessile and other pedicellate. The sessile floret is fertile and contains palea, three stamens, one ovary and a stigma with two feathers. Lemma is absent. The pedicellate floret is sterile and has only lemma. At the base of the floret, there are long silken hairs known as fuzz or fluff which help to disperse the seeds. Two short edge shaped lodicules are present opposite the palea near the base of the ovary. Flower / floret The flowers are borne in paired spikelets, one sessile and other pedicellate. Both spikelets have two florets; one is sterile and is represented by a delicate pointed lemma. The upper floret of each is 91

Pedicellate spikelet

Stigma

Sessile spikelet

Anther

PART OF INFLORESCENCE OF SUGARCANE FUZZ / TRUE SEEDS OF SUGARCANE

bisexual without lemma. Androecium Three stamens with large bi-lobed anthers are present in a whorl. The indehiscent anthers are usually yellow or pale yellow, white dehiscent anthers are brown or purple. Gynoecium Ovary is round on the central surface with a single ovule. The pistil has two long terminal sytles with large brush like stigma. Lodicules At the base of ovary opposite the palea are two short edge shaped lodicules.

Reproductive organs

Mode of Pollination Protogyny leads to cross pollination in sugarcane. In commercial practice, sugarcane is propagated by means of seed cane. The vegetative variety remains true to type. In sugarcane no variety breeds true from seed. Each seed produces a distinct variety. Once a variety is obtained, it is kept pure by vegetative

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propagation. Thus the population structure of a variety is heterozygous homogeneous. Anthesis The canes flower from Oct.Dec. in Northern Hemispher and March-June in Southern. Anthesis takes place early in the morning from 5 to 6 a.m. An arrow takes about one or two weeks to complete blossming. The opening of flowers commences from the top and proceeds downwards. Pollen Viability Pollen grains remains viable for a short time after anthesis but stigmas are persistent. Emasculation The minute nature of spikelets create problem for emasculation. The general practice is to use the entire inflorescence as a unit. The sugarcane breeders select clones for female parents that are highly male sterile to be used as female parent in the crossing programmes. To have the inflorescence at optimum levels of height and to avoid contamination for hybridization, some techniques have been developed to induce rooting of the nodes of standing canes. ¾ In Java, the cut end of the male stalk is placed is water and the stalk is changed every 2-3 days. ¾ The tile pot method of isolating arrows which was in practice in India was replaced by stove pipe. ¾ Presently the use of alkathene for marcotting has bees adopted.

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¾ The sulphureous acid method developed from Hawaii is adopted by many countries. Recommended solutions: 1. 150 ppm sulphurus acid 2. 75 ppm phosphoric acid 3. 37.5 ppm sulphuric acid 4. 37.5 ppm nitric acid. Pollination: The female parent is pollinated by pollen from male parent every day for 5-10 days. Alternatively, the male inflorescence is tied with the female inflorescence to receive continuous pollen naturally. a. Lantern method: A male sterile female parent and male parent are kept together in lantern for isolation. b. In another approach several desired male and female parents are kept together under a crossing shelter.

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Floral Biology of Cotton Family : Malvaceae Genus : Gossypium Species Cultivated species

: arboreum, herbacium (Asiatic cotton) hirsutum, barbadence (American cotton) Related species : anomalum, thurberi, tomentosum Chromosome Numbers : Asiatic cotton 2n = 26 American cotton 2n = 52 _____________________________________________________________________ Introduction Cotton is mainly grown for its lint. This is basically used in textile industries. Seeds and seed oil are important byproducts. The oil of cotton is used for various purposes including cooking, and oil cake as animal feed.

Fig. 10.1

Cotton is cultivated in India from sub-Himalayan region of Punjab in the north to Kerala in south and from dry regions of Growth of a fruiting branch from the main stem. The Kutch to high rainfall areas of branch forms in the axil above a main stem leaf. Manipur in east. Gujrat is largest producer in India followed by Punjab and Maharastra.

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Among all the cotton growing countries, India occupies the foremost position in cotton acreage. Fruiting Branch: (Fig. 10.1) A fruiting bud, called a square, begins to form at the initiation of the fruiting branch. The first square produced on a fruiting branch is referred to as a first-position square. As this square develops, the portion of the fruiting branch between the main stem and the square also elongates. This portion of the fruiting branch is also called the internode, similar to the portion of the main stem between main-stem nodes. An axillary meristem also develops adjacent to this square. The axillary meristem produces a second position square and subtending leaf. As many as four squares may be produced in this fashion on a fruiting branch. The branches on a cotton plant can be classified as either vegetative branches (monopodia) or fruiting branches (sympodia). Vegetative branches, like the main stem, are referred to as monopodia (meaning “single foot”) since they have only one meristem. Because vegetative branches have only one meristem, they grow straight and erect, much like the main stem (Figure 10.2). Vegetative branches can also produce fruiting branches.

Fig. 10.2

Source: pubs.caes.ua.edu/caespus/pucd/B122.htm

A cotton plant with leaves removed shows the straight growth habit of the main stem and the vegetative branch.

A fruiting branch with leaves removed shows its zig-zag growth habit.

The branches from which fruiting buds arise are called fruiting branches, or sympodia (meaning “multiple feet”), because each fruiting branch contains multiple meristems. Fruiting branches have a “zig-zag” growth habit, as opposed to the straight growth habit of the vegetative branches (Figure 13). The initial growth of a fruiting branch is terminated once a fruiting bud forms. The fruiting branch, however, initiates a new growing point, called an axillary meristem. The axillary meristem is located at the

96

base of a leaf that subtends the newly formed fruiting bud. The “zig-zag” growth habit is a consequence of the stop-and-go growth of the fruiting branch.

Fig. 10.3

A defoliated cotton plant shows the 3/4 alternate phyllotaxy of branches. Each branch is 3/8 of a turn around the stem from the branch below it. The branches form from the axils of main stem leaves. (b) A diagram of the general timing of flower emergence from buds on the fruiting branches by fruiting position. Source: pubs.caes.ua.edu/caespus/pucd/B122.htm

The first fruiting branch will generally arise at main-stem node 5 or 6. A cotton plant will mainly produce fruiting branches, but several common environmental factors such as low population density, insect and disease pressure and over-fertilization can cause vegetative branches to form. Vegetative branches are produced after fruiting branches, and develop at nodes directly below the node at which the first fruiting branch was developed. For instance, if the first fruiting branch is initiated at mainstem node 5, a vegetative branch may develop at main-stem node 4. New fruiting branches are generally believed to develop approximately every 3 days, although recent studies show that this developmental rate varies. Squares are produced at new positions on a fruiting branch approximately every 6 days. The age of fruiting structures on a cotton plant can be mapped according to this time sequence (Figure 10.3b).

97

Formation of the Cotton Bud from Square to Bloom During the 21-day period from square to bloom, there are several recognized developmental stages of the cotton flower bud. A “pinhead” square is the first stage at which the square can be identified. The next stage of square growth is “match-head” or “one-third grown” square. Just prior to the time the flower opens, a candle shape can be seen (Figure 10.4). This period of square development prior to bloom is called “squaring.”

Fig. 10.4

Development of the bud from match head square (a) to flower (e) involves both a size increase and petal development. Two bracts have been removed from each square, candle and bloom to show this development. Source: pubs.caes.ua.edu/caespus/pucd/B122.htm

Once the cotton begins to bloom, it is said to be “flowering.” A cotton plant typically blooms or flowers for about 6 weeks. Thus, until the cotton begins to produce fruit, the stage of development is discussed in terms of leaves or nodes. Once fruiting begins, the stage of cotton development is discussed in terms of square development and the number of nodes. Once blooms are present, the stage of cotton development is discussed in terms of weeks of bloom. Flower The flowers are extra axillary, terminal and solitary. On the account of the sympodial development of the fruiting branches, the flower opening follows a spiral course in

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Fig. 10.5

Fig. 10.6

A Petal

Bract

Subbracteal Nectary

B

C

Stigma Style Staminal column Anther Filament Ovule Calyx Floral nectary Subbracteal nectary

acropetal and Inner bracteal nectary centrifugal Cotton flower: A-Side view showing one subbracteal nectaries; B-Bracts succession. The slightly spread to show one of the three inner bracteal nectaries; innermost bud of the C-L.S. of flower lowest branch is the (Modified from Source: pubs.caes.ua.edu/caespbs/pbcd/B152.htm) first to open while the outer most bud of the highest and youngest branch is the last to do so. Each flower is subtended by involucres (epicalyx) of usually 3 unequal leaves like bracts, which may be free, as in case of American cotton or united, as in case of Asiatic cotton. They are generally large, uneven, entire or notched/toothed 99

corresponding to the primary vein. Characterstic satellite hairs are found on the outer surface. Bracteoles, alternating with the bracts on the inside of involucre or standing on either side of the small bract, may be present. Extra floral nectaries occur sometimes on the apex of the peduncle below the auriculate base of the bracts. The flower is bisexual complete and regular, pentamerous, hypogynous and actinomirphic. Stages of Flowering Flowering is important to cotton production because pollinated flowers form cotton bolls. The bloom process takes several days, and bloom age can be estimated by the bloom characteristics Fig. 10.7 (Figure 10.7). On the PINK day a flower opens it is FLOWER white in color. Pollination of that WHITE flower usually occurs FLOWER within a few hours after the white flower opens. On the second day the flower will have a pinklike color, and a red PINK PINK color on the third day. SHRIVELLING SHRIVELLED Approximately 5 to 7 FLOWER FLOWER days after a flower Development of a cotton bloom. A white flower emerges on day appears it usually dries 1 (a), then gradually darkens and takes on a red color during days 2, 3 and 4 after emergence (b and c). The bloom eventually and falls from the plant dries up and either falls off or becomes a bloom tag (d). exposing the developing boll. Occasionally a flower will stay attached to the developing boll for a longer period of time. This is referred to as a bloom tag (Figure 10.7d). Source: pubs.caes.ua.edu/caespus/pucd/B122.htm

Androecium The stamens are numerous and united to form a tubular sheath (staminal column) which surrounds the pistil, except for the exposed portion of the style and stigma. The stamens are monadelphous and epipetalous. The filaments of stamens though appearing to arise in five fascicles really contain ten well-defined groups of stamens arranged in paired vertical rows. The number of stamens may vary from 90-100. Petalody of cotton anthers has been reported in Karunganni cotton (G. indicum).

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There is a little elongation of the filament in the beginning but it lengthens rapidly prior to blossom state. The anthers are reniform, bilocular, dehisce along a single line over the top of the anther and liberate spinose pollen grains. There are about 10,000 pollen grains in a flower. Some of the pollen grains develop more than one pollen tubes on the stigmatic surface.

Fig. 10.8

GYNOECIUM

Gynoecium

The gynoecium consists of three to five carpels. Each carpel has a syncarpous style passing through the staminal tube. The ovary is superior and ovules are attached to the parietal placenta of the loculi. The placentation is axile. Style is glandular and style club shaped. The style varies in length and splits near the apex into 3, 4, or 5 parts depending on the number of carpels. The dehiscence of the boll is along the dorsal sutures. Calyx The calyx has 5 persistent, shallow, cap like sepals with variable lobes. It is truncate, and undulate that adheres tightly to the base of the boll as it

GYNOECIUM develops. In certain genotypes three extra floral nectaries, irregularly triangular in shape and surrounded by stiff hairs, are present in the outer calyx. The sepals possess a number of globular sub-epidermal glands erratically. Inside the calyx, 5 greenish obvoate or spatulate organs rudimentary and small in size are frequently seen alternating with the lobs. These intercalicary

CALYX

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organs have been interpreted as supernumerary “calyx lobs” or elements”.

“free stipular

Epicalyx The epicalyx consists of three persistent modified leafy bracts, also called as bracteoles or Squares. Sometimes these are small or minute and cordate, toothed or entire, and rarely caducous. Corolla It is tubular consist of five obcordate petals, alternating with the calyx lobes and overlapping the next one in the series in a convoluate manner. The petals may be white EPICALYX creamy white, light yellow or purple. In some species a spot of purple or dark red colour called ‘Eye’ is found on the claw/base of petals. It is due to the presence of anthocyanin content whose intensity may vary from genotype to genotype. The first day after the anthesis the corolla changes its colour to pinkish tone and then to red during the following day. It withers and falls on the third day, along with the staminal column and stigma leaving the ovary, calyx and epicalyx intact. COROLLA: COLOR VARIATION Fruit Fruit is a loculicidal (3-5 loculed) capsule termed boll. The development of the fruit (boll) begins with the fertilization, and shedding of withered floral organs enclosing it. Bolls developing under falling temperature will need more days to mature than those growing under rising T.S. OVARY temperature. The ripened boll contains seeds varying from 1 to 9 in each locule. A fair percentage of seeds remain undeveloped due to non-fertilization, heredity and environment. These are called “ motes”.

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Seed: Completely developed seed attains pear shape. The size may vary depending upon genotype and environment where it was grown. Seed may have short hairs (called fuzz) or may be hairless (naked). All cultivated cottons bear long fibers called lint. Its color, length and fineness varies from variety to variety and species to species. Anthesis & Pollination

Mode

of

Cotton is an often crosspollinated crop. The amount of natural cross-pollination ranges from 5 to 30%, COTTON depending upon number of BOLLS insects which brings it about. They usually travel a few yards only within a cotton field. The twisted corolla emerges from bracts a day prior to pollination, and during anthesis corolla changes from white, cream to pink and gradually turns red and ultimately it is shed away. When anthers dehisce the pollen grains fall directly on the stigma or may be carried away by insect or wind. Pollen is wind-borne only to a very slight extent, if at all, on account of its heavy sticky nature. Fertilization is complete after pollination in 36-40 hours. There is much variation in the time of flower opening. American types open earlier than Asiatic types. Asiatic cotton open between 8-10 a.m. Temperature and humidity also affects flower opening. Selfing Since cotton is often cross pollinated and a small amount of out crossing usually takes place, it is necessary to cover a bud with a paper bag a few hrs before it opens. Therefore, the flowers which are expected to open next morning are bagged with butter bags to prevent cross pollination. If the bag is placed too much in advance of the opening the flower the boll may be shed because of high temperature developing in the bag. The deposition of foreign

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pollen may also be avoided just by putting the tips of the corolla together with a rubber band, a clip or with a piece of wire or string.

STAGES OF FLOWER DEVELOPMENT TO BOLL FORMATION Emasculation & Pollination Select those buds in which anthesis is to occur next day. Usually white buds are selected for emasculation. Remove epicalyx, corolla and staminal column with an emasculating instrument. Great care should be taken that there is no injury to stigma. The application of 100ppm gibberellic acid solution at the base of anther at the time of the emasculation improves seed set. To protect the stigma of the emasculated bud from contamination of foreign pollen, a soda straw of optimum length or a paper bag may be used. Proper tagging is also done. Emasculation and pollination should be completed simultaneously in the morning between 8.30 to 10.30a.m. The extent of cross-pollination in cotton ranges from 5-30 per cent. In some cases, cross-pollination up to 50 per cent has been reported. That is why cotton is considered as an often cross-pollinated crop. The out crossing is mainly carried by insects particularly bees. The flowers which are expected to open next morning are bagged with butter bags to prevent cross pollination. The pollen grains are collected from the ripe anthers of the flowers of the male parent with small sections of the soda straw. The anthers are slipped down or the stigma from the soda straw. The bracts are pulled up around the soda straw and are tied firmly to hold it. It is desirable to do both emasculation and pollination on the same day to avoid the drying up of the stigma.

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Hybrid seed production There are three methods suggested for producing F1 hybrid seed: 1. Hand pollination and natural cross pollinations. 2. Use of chemical gametocides to induce male sterility. 3. Use of genetic or cytoplasmic male sterility. As the commercially utilizable male sterility is yet to be achieved, hybrid seed production has to depend on hand emasculation on an extensive scale. This indispensability of hand emasculation has rendered the hybrid cotton seed production more costly, labour dependent, restricting the area under seed production to one or two acres per farmer. This constraint has indeed restricted the production of hybrid cotton seeds. Such restriction is not found in case of any other crops as the male sterile lines are invariably available in all other crops. The enormity of work involved in hybrid cotton seed production can be realized by the extent of crossing and emasculation work need in each seed plot. It is necessary to emasculate 176633 female flowers and collect pollen from 22080 male flowers, cross and bag 176633 flowers to obtain 151 kg of hybrid seeds (based on the studies conducted by Sheriff and Shivandaiah 1974). Further, the stigma receptivity and pollen viability have put many restrictions on hybrid seed production. The emasculation and crossing can be carried out between 4 and 6 p.m. and 9 a.m. and 11 a.m. respectively. Any fluctuation in timings leads to poor seed setting or admixture of pollen.The crossing work has to be carried out for about 40-45 days to cover the entire period of flowering. It is also necessary to harvest the kapas from the crossed bolls separately from uncrossed bolls to avoid possibility of admixture of seeds. Discovery of cytoplasmic male sterility in cotton has renewed interest in the utilization of hybrid vigour in cotton by growing first generation hybrid increased following the discovery of cytoplasmic male sterility in cotton which was obtained by transferring G. hirsutum chromosomes into G. harknessii cytoplasm. Fertility is restored by a fertility restorer (Rf) gene from G. harknessii and a gene from Pima cotton that enhances fertility. An obstacle not overcome is that of obtaining sufficient cross pollination by bees and other insects in the seed production field to make hybrid cotton economically feasible. In India seeds of hybrid cotton are commercially produced by hand emasculation and pollination, or by hand pollination of genetic male sterile cotton, the labour

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required for hand pollination makes this procedure economically unfeasible in countries with high labour costs. Following are the schemes for hybrid seed production in cotton: A. CONVENTIONAL METHOD: This method of cotton hybrid seed production is described below with a suitable example of a cotton hybrid currently in practice. Hybrid Seed Production : HHH223 Parentage:

H1157 (Female) x H1220(Male) (G. hirsutum x G. hirsutum)

For the seed production in an area of one acre, the female parent is to be raised in 80 per cent and the male parent in 20 per cent area. Spacing For female parent : Line to Line: 1.35m (4.5 ft) Plant to Plant: 30 cm Male parent : Line to Line: 0.67m (2.25 ft) Plant to Plant: 30 cm Synchronization Synchronization is not a problem in these parents. However, the onset of flowering in both the parents can be adjusted by manipulating date of sowing so that flowering in male and female flowers can coincide. Seed rate Female: 800g and Male: 200g Emasculation and pollination These steps are more or less same in all the genotypes. Slight modifications may be required under certain situations that can be tackled by the concerned cotton breeder. However, general procedure is: •

Emasculate and pollinate as far as possible in the buds appearing during the first six to eight weeks of reproductive phase (preferably up to August 1 – September 20 in May sown crop) to ensure good setting and development of bolls.

•

Restrict emasculation to each day evening from 3 to 6 PM and pollination next morning between 9 AM to 1 PM.

•

Emasculated buds may be protected with butter paper bag. Tie a thread to the pedicel of the bud immediately after pollination.

•

Nip the top and side shoots to arrest further vertical and horizontal growth, respectively. 106

•

Normally one flower from the male parent will cover 5 to 10 flowers of the female parent for crossing.

•

Keep the isolation distance of 30 m from the same species of cotton and 5 meter from the other species.

B. GMS BASED METHOD In this method there is no need of emasculation. Seedsetting is far superior to the conventional method. This method of cotton hybrid seed production is described below with a suitable example of a cotton hybrid currently in practice. Hybrid: HHH 287 (G. hirsutum) Parents: HGMS 1 (female) and HHM-1 (male) [both belong to G. hirsutum] • • • • • • • •

Sowing plan is done as shown above. GMS segregates into 1: 1 of fertile heterozygotes and recessive homozygotes Remove all the fertile heterozygotes producing pollen grains (powdery mass). Pluck / remove all the bolls formed / fresh flowers from the male sterile plants before starting the hybrid seed production programme. Pollinate f lowers of male sterile plants every day with the pollen of fertile line. Nip the top and side shoots to arrest further vertical and horizontal growth, respectively. Normally one flower from the male parent will cover 5 to 10 flowers of the female parent for crossing. Keep the isolation distance of 30 m from the same species of cotton and 5 meter from the other species.

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Floral Biology of Chickpea Family : Sub family : Genus : Species : Chromosome no. : Origin : Related species :

Leguminoceae Papilionaceae Cicer arietinum 2n = 14, 16 Near Eastern Centre (West Asia ) C.reticulatum. C.pinnatifidum. C.songaricum

Chickpea is the world’s second most important pulse crop in terms of area sown and third in annual production. The main producing region is the Indian subcontinent where it is the chief pulse and a major source of protein for the predominantly vegetarian population (Fig. 11.1). Two main categories of chickpea are recognized which are distinguished mainly by their seed characteristics. They are (1) the Desi Fig. 11.1 types, which are relatively smaller, angular seeds with rough yellow to brown coloured testas; (2) Kabuli types, with large, more rounded and cream coloured seeds.

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Two main categories of chickpea are recognized which are distinguished mainly by their seed characteristics. They are (1) the Desi types, which are relatively Fig. 11.2 smaller, angular seeds with rough yellow to brown coloured testas; (2) Kabuli types, with large, more rounded and cream coloured seeds (Fig. 11.2). Botanical Characteristics Chickpea is an indeterminate annual Kabuli Desi herbaceous shrub with yellowish green to bluish green or purple foliage. Plants are erect, semi-erect or prostrate. The main stem is round and the branches quadrangular and ribbed. Branches originate from the first node in the axils of simple scale-like leaves. Basal primary branches on the main stem are more vigorous than those that arise at the upper nodes. Plants are profusely branched with secondary and tertiary branches at various levels. Chickpea possesses a deep -tap root system with three to four well-defined rows of lateral roots. The primary and secondary roots may Fig. 11.3 develop large lobbed nodules that contain Rhizobia which fix atmospheric nitrogen symbiotically. The first two nodes on the main stem have simple scale-like leaves fused with two lateral scale-like stipulae. Leaves are borne singly at each node from the third node onwards. They are compound, arranged in an alternate phyllotaxy and generally imparipinnate having 11 to 13 leaflets. Types with a highly dissected compound leaf or with simple leaf larninae or multipinnate also occur. The leaf structure is bifacial with stomata in equal abundance on both the upper and lower leaf surfaces. The normal floral botany of chickpea is fairly consistent with a single monocarpellary flower on each peduncle with five sepals, five (2+2+1) petals, and ten stamens in diadelphous (9+1) condition. Occasionally, twin polycarpellary flowers per peduncle are also reported. The flowers are borne axillary on short jointed

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peduncles arising from the leaf axil and are situated opposite the leaves. They are white, pink, purple or blue in colour. Yellow deformed buds, which desiccate without opening, and termed pseudo-flowers (Fig. 11.3). Floral Biology Chickpea is predominantly a self-pollinated crop, perhaps, obligatory since pollination takes place at the hooded bud stage. Pollen is most viable when the flower is half opened, and pollination occurs 12 to 24 h before the flower is fully expanded. During the early stages of green bud development and enlargement, the style Flowers are elongates and the stamens borne in the axil remain clustered at the base of of leaf the ovary. At the so called Fig. 11.4 white bud stage, when white petals have emerged from the calyx but are still enfolded, filaments elongate so that anthers are positioned close to the stigma. At this stage, pollen is shed and most of it lands on the stigmatic surface. It adheres to papillate cells in a small localized area at the most distal region of the stigma. Full bloom occurs approximately 24 h after pollen is shed. The white bud stage is the stage of floral development that has been empirically suggested as most appropriate for hybridization in chickpea because at this stage, stigma is most receptive and pollen viability is high. Crossing attempts involving either emasculation or no emasculation have given erratic results (23 to 98% hybrid seeds) and this compounded by the low rate of natural seed set (18 to 52%) due to flower drops has hampered works on genetic and breeding research. The low rate of success may be attributed not only to the stage of bud development but also to the small number of papillate cells on the stigmatic surface that are receptive to pollen. Thus flowers for cross-pollination should be selected carefully so that pollen with the highest viability is available.

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Flower: The flower is typically papilionaceous (Fig. 11.5)., zygomorphic, solitary, axillary (Fig.11.4). polypetalous and bisexual, with vaxillary aestivation. However cultivars with two or three flowers are known. The peduncle is short jointed and arises from the leaf axils opposite to the leaf. The flowers are small, white and violet. Each flower has 5 sepals and 5petals. Out of 10 stamens, 9 are fused to form a staminal column and 1 is free. The carpel with its style is born laterally on the ovary. Calyx: The calyx (8 to 10 mm) is composed of five partly joined sepals which makes it gamosepalous. The two sepals are large and three are small. The calyx tube is obliqe, gamosepalous, lanceolate, and densely covered with hairs (Fig. 11.5).

Standard

Papilionaceous flower Wings

Keel Calyx (ONE SEPAL REMOVED) (hairy)

Standard (back view)

Fused sepals at the base

Fig. 11.5 Corolla: The corolla (8 to 11 mm ) may be greenish white, purplish pink , red or FRONT AND BACK VIEWS blue in color. The standard OF CHICKPEA FLOWER petal is broad and clawed, the wings are free and the keel incurved. Thus corolla consists of 5 petals (2+2+1) (Fig. 11.6).

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Standard

Wing I

Wing II

Keels

Fig. 11.6

COROLLA (STANDARD + WINGS+ KEELS) Androecium: The androecium is composed of 10 stamens nine fused and one is free (9+1) .The length of stamens varies from 6 to 8 mm. The anthers are bi-celled, orange and basifxed (Fig. 11.7). Gynoecium: The gynoecium consists of a superior ovary with a terminal slightly curved or upturned style and blunt knot- like stigma (Fig. 11.9) The developmental stages of bud and flower of chickpea have been categorized as follow. A. Closed bud stage: in this stage stigma is immature and anthers are still at the base of the bud.

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B. Hooded bud stage: the corolla is elongated, and the anthers are at the half of the height of the style . The stigma is receptive and remains so until stage D. Emasculation is done at this stage. C. Half open flower: the anthers now have reached the same height as the stigma and the pollen is mature just before the anther is dehisced. Pollination now takes place and keel remains closed preventing any pollen from reaching the stigma. Pollen grains for crossing are collected/selected at this stage. D. Fully open flower: The anthers are shriveled, while the standard and wings are fully expended. Fertilization takes place 24 hours after pollination. E. Fading flower: the post fertilization stage, in which ovary starts to elongate. Fruit: The fruit is an inflated pod, with 1 , 2 , or 3 seeds (Fig. 11.10) attached to the ventral suture. The seeds are beaked, round to semi-round wrinkled or semiwrinkled . The seed coat is either brown, light brown, fawn, yellow, orange, black, white or green. The carpel with the style is borne laterally on the ovary.

9 fused stamens

Staminal column Calyx (sepals removed)

Stigma Style Ovary

Anther

One free stamen Peduncle

Fig. 11.7

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Mode of pollination:

Gram is considered to be highly self pollinated because of

Fig. 11.8

Calyx Pod cleistogamy, although small amount of cross pollination is observed due to insects particularly bees. Emasculation: Emasculation in gram is generally performed in the Fig. 11.9 afternoon. The flowers in hooded bud stage are selected for emasculation and the flowers and buds are removed. The stamens are removed by pushing keel petal gently by holding the bud between thumb and first finger. Care should be taken that gynoecium parts are not injured during emasculation, there is no need of bagging and tagging is done as usual. (Fig. 11.11). Pollination: The anthers for pollination are collected at half open flower stage. Pollination is done next morning. Apply pollen to the stigma lightly by gently anthers against the stigma.

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DEVELOPING GRAIN

Fig. 11.10

pressing

Fig. 11.11

EMASCULATION STEPS IN CHICKPEA

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Floral Biology of Pigeonpea

Kingdom: Division: Class: Order: Family: Genus: Sub-tribe: Species:

Plantae Magnoliophyta Magnoliopsida Fabales Leguminosae / Fabaceae Cajanus cojaninae cajan

Scientific Name:

(Cajanus cajan (L.) Millspaugh) Common Names: Angola pea, Congo beans or pea, Red Gram, Yellow Dhal, Origin: South and Southeastern Asia. Fig. 12.1

Pigeonpea (Cajanus cajan (L.) Millspaugh) (Fig. 12.1, 12.2 and 12.3) is PIGEONPEA one of the major grain legume (pulse) crops of the tropics and subtropics. It is the second most important pulse crop of India. Production is about 2 million tones annually world wide, of which a little less than 85% is produced in India. Although pigeonpea ranks sixth in area and production in comparison to other grain legumes such as beans, peas, and chickpeas, it is used in more diverse ways than others. Besides its main use as dhal (dry, dehulled, split seed used for cooking), its tender, green seeds are used as

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Mature pods Flowers

Fig. 12.2

Pigeonpea plants

a vegetable, crushed dry seeds as animal feed, green leaves as fodder, stems as fuel wood and to make huts, baskets, etc., and the plants are also used to culture the lac-producing insect. It is grown on mountain slopes to reduce soil erosion. Pigeonpea seed protein content (on average approximately 21%) compares well with that of other important grain Fig. 12.3 legumes. ICRISAT holds about 13,544 accessions of this crop in trust under the Food and Agriculture Organization-Consultative Group for International Agricultural Research agreement (ICRISAT web page). Pigeonpea is cultivated in more than 25 tropical and sub-tropical countries, either as a sole crop or intermixed with such cereals as sorghum (Sorchum bicolor), pearl millet (Pennisetium glaucum), or maize (Zea mays), or with legumes, e.g. peanut (Arachis hypogaea). Pigeonpea may be self-pollinated crop, but up to 40% cross -pollination can occur. Therefore, it comes under the category of Often Cross-pollinated crops. Pigeonpea plant types may be determinate to indeterminate. Floral structure Inflorescence: (Fig. 12.4, 12.5) The flowers are borne on short axially or terminal racemes and are usually about 2cm in length. They vary in colors from pale-yellow to orange often with the standard striped or splotched with dark red or purple. Flower colour may also be yellow or yellow with purple veins or diffuse red. Pigeonpea has typical papilionaceous, bracteate bracteolate flowers consisting of 5 sepals

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(gamosepalous), 5 pleats (polypetalous) and one carpel with the style born

Fig. 12.4 Immature/ young flowers

Mature / older flowers

pods in the oldest flowers

Pigeon pea Inflorescence: Raceme laterally on the ovary. Petals and Sepals (Fig. 12.6, 12.7, 12.10, 12.11) The petals are large and brightly colored and 5 in number, comprised of one standard, two wings and two keels. Sepals are also 5 in number.

Raceme (upper half)

Reproductive Organs: Stamen (12.7, 12.9) It consists of a slender stalk or filament, which supports an anther. These are 10 in number, 9 fused to form a staminal column and one is free i.e. are in diadelphous condition. The ovary is unicarpellary, unilocular, superior, sub-sessile with 2-9 ovules; style long, filiform, much upcurved; stigma capitate and glandular papillate. Fig. 12.5

Anthesis and Mode of pollination Pigeonpea flowers can be self-pollinated or cross-pollinated. Self-pollination occurs in bud before the flower opens. Majority of workers have reported the range of cross-pollination from 5-40%.Although the stigma is completely covered with the pollen of its own flower, considerable outcrossing occurs in pigeonpea.

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P igeo n p ea Fully open flower FRONT VIEW

Keels (fused)

Standard

Calyx

Developing Pod

Wings

P igeo n p ea Fully open flower

SIDE VIEW Keels (fused)

Wings Standard

P igeo n p ea Fully open flower

BACK VIEW

Developing grains

Calyx

Keels (fused)

Wings

Standard Calyx

Fig. 12.6

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Pigeonpea

Free stamen’s attachment point Gynoecium (yellow)

Keel 2 (light yellow)

Calyx

Wing 1 (yellow) Staminal column of 9 fused Anthers (white) Standard (red)

PFloral igeo npea B iology

Keel 1 (light yellow)

Wing 2 (yellow)

T.S. of flower

© A.K. Chhabra

Make a cut and see the T.S

g g b

b c a d

c

f e

a

d

b c

Upper portion

a

a: free anther b: gynoecium c: staminal column of 9 fused anthers d: keels e: standard f: wings g: calyx

f d e

f

e

f

e T.S. o f t h e Flo wer

PFloral igeo n pea B iology

T.S. of the Flower

© A.K. Chhabra

Fig. 12.7

The foreign pollen has an advantage over native pollen in affecting fertilization. It has been proven by pollinating the flower buds by foreign pollen. It was observed that the percentage of ‘self’ was negligible when flower buds were pollinated with

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Pigeonpea Gynoecium Ovary

Stigma Style

Fig. 12.8

Pigeonpea Androecium 9 fused stamens Forming staminal column

One free stamen anther

Fig. 12.9

foreign pollen without emasculation. Some of the reasons attributed to it are delayed germination and slow pollen tube growth of the native pollen. Such mechanism provides sufficient gap for foreign pollen to be introduced into the stigma and thus it favours outcrossing. Among the insects involved in crosspollination are Apis florea, Apis dorseta and Megachile spp. Anthesis normally occurs between 8.00 a.m. and 5.00 p.m. and flowers may remain open for 6 to 48 h. Flowering period is influenced by weather conditions. Emasculation and Pollination Flowers are generally emasculated in the evening and pollinated in the next morning. For emasculation, flowers that will open one or two days later are selected, and the rest of the flowers and the buds in a branch are removed. The

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stamens of the selected buds are removed with a pair of a fine forceps by gently pushing the keels apart. The emasculated floral branch is then bagged.

Wing 1

Standard

Wing 2

Keels (fused)

Fig. 12.10

Parts of corolla sepals

Calyx

Unopened Only four sepals are visible

gam ose palo us

Unopened Only 3 sepals are visible

Cu t-o p en ed Showing 5 sepals In gamosepalous condition

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Fig. 12.11

Dh en ch a surrounding pigeon pea fields (it provides isolation for seed production plots)

Pigeon pea Fig. 12.12

Self pollination To ensure selfing the flowers need to be bagged. This is because insects may sometimes carry pollen to the stigma and bring about cross-pollination. Seed Production: (Fig. 12.12) Seed production is done in isolation using dhencha as a border crop to protect the seed crop from contamination through foreign pollen. CMS lines are also available and are under test for use in seed production programmes.

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Floral Biology of Field Pea Common Name: Genus: Species: Family: Chromosome no: Scientific name: L.

Field pea Pisum sativum Papilionaceae 2n =14 X=7 Pisum sativum

Fig. 13.1 Peas without

Field pea (Pisum sativum L.), a native tendrils of Southwest Asia, was among the first crops cultivated by man. It is an annual herbaceous legume adapted to cool, moist climates. It is one of the oldest cultivated plants.

Fig. 13.2. Peas with tendrils

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Field pea is grown for forage or dry mature seeds, which are used as food or feed. It is also used for soil improvement; it makes good hay crops when mixed with grain. This mixture may also be used to make excellent quality silage of high feeding value, also as dry edible peas. Used for winter clover, green manure, soup preparation etc. Field pea is a self-pollinated crop. However cross-pollination can be quite extensive with some genotype and in some environments, ranging from 0-60 %. It is less than 1% in commercial cultivars. Field pea is of the indeterminate (climbing) type or determinate (bush or dwarf) type. (Fig. 13.1, 13.2, 13.3) Flowers are borne on racemes arising in the axils of the leaves. In most varieties, the blossoms are reddishpurple or white. Pods are about three inches long and contain four to nine seeds. Seed may have a green, yellow or cream colored seed coat and are classified as such.

Fig. 13.3. Plant

structure

Floral biology

Fig. 13.4. Flower

(Back view)

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Flower (Fig. 13.4, 13.5, 13.11) Flower is zygomorphic, cleistogamous, reddish purple or lavender or white in color. Inflorescence is a raceme arising from a leaf axil. There are usually 1-3 flowers per raceme, some genotypes may have more. The number of flowers per peduncle may vary from one to several on the same plant . Floral initiation begins at the lowest node and proceeds sequentially up the stem.

Fig. 13.5. Flower

Calyx (Fig. 13.4, 13.11) It is composed of 5 sepals in gamosepalous condition. Two sepals are behind the standard, 2 subtending the wings and one anterior subtending the keel. Corolla (Fig. 13.4, 13.5, 13.11) It consists of five petals in (2+2+1) condition having 1 standard, 2 wings and 2 keels that are fused except at their base. They cover the pistil and the stamens. The standard has notch in the center. Aestivation is vexillary. Androecium (Fig. 13.6, 13.11) It consists of 10 stamens in 9+1 arrangement. The filaments of 9 stamens are joined for much of their length to form a staminal tube around the ovary. The 10th stamen is free. When young, the filaments are shorter than the style but elongate by the time of pollen shedding.

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Fig. 13.6

Gynoecium (Fig. 13.7) Ovary is superior, green and flattened containing 5-12 ovules. The style is slightly flattened, Cylindrical and bends at right angle to ovary. It recurs towards the ovary near its tips .The tip has a brush of stylar hairs. Stigma is elliptical, viscous and sticky. Anthesis Anthesis proceeds sequentially upward from node to node .It begins at the lowest floral node and proceeds upward. With cool, moist environmental conditions 5-6 days may separate anthesis between nodes. Under hot, dry condition the separation may be only one day.

Emasculation (Fig. 13.10) It can be done at any time of the day. The flowers are emasculated just prior to pollination. Usually emasculation is carried out in the morning. The right stage of

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Fig. 13.7. Gynoecium

emasculation is when the plant just begins to flower and the buds are not yet developed. Pollination Pollination naturally occurs 24 hour before flower opening and the pollen placed on stigma germinates in 8-12 hour. Fertilization occurs about 24-28 hours after pollination. Stigma is receptive several days before anthesis until one day after the flower wilts. Pollen viability is from the time of anther bursting until several days thereafter. Freshly dehisced anthers are collected and transferred to the tip of the stigma with the help of a toothpick, forceps, cotton swap or camel hair brush.

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Fig. 13.8. Hanging pods in peas

Fruit Hanging pods are green or yellowish green. (Fig. 13.8, 13.9)

Fig. 13.9. Pods and peas seeds

Fig. 13.10. Emasculation in peas

129

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Floral Biology of Groundnut Crop Name: Genus: Species: Family: Chromosome No.: Origin: Related Species:

Groundnut Arachis hypogaea Leguminosae 2n = 40 Brazil A. sylvestris, A. pusilla

Groundnut (Fig. 14.1, 14.2, 14.3) is primarily used as an oilseed corp. Large quantities of it are also consumed directly as food. The groundnut plant is also used as a fodder crop. The oil cake is an important source of protein and fed to the animals and is also used for manure. The genus Arachis includes annual and perennial diploids (2n = 20) and annual tetraploids (2n = 40). The cultivated Arachis hypogaea L. is allotetraploid with 2n = 40. Floral Biology Inflorescence (Fig. 14.4, 14.12) The flowers are born either solitary or in clusters (raceme) in the axils of the leaves, near the base of the plant. Flower Fig. 14.1.Groundnut plant number per inflorescence varies with sketck-Photographed at ICRISAT museum

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Fig. 14.2 cultivars. A flowering branch never occurs at the same node as a vegetative branch, although they may appear to do so because of the shortness of the internodes. In the variety hypogaea, the inflorescences are simple and expand slightly in length during maturation. In the variety vulgaris, the inflorescences are compound and expand moderately. In the variety fastigiata, the inflorescences are simple, but may elongate to form a conspicuous long branch that may occasionally terminate in leaves. The length of the inflorescence is also dependent on the cultivar and may exceed 10 Fig. 14.3 cm in some cultivars

Close-up view of crop

Flower The flower is papilionaceous. It is complete, zygomorphic, sessile, bracteate with a reduced pedicel and yellow in colour. What appears to be a pedicel is actually an elongated hypanthium (Fig. 14.4, 14.12)

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Fig. 14.4 Standard

Wings

Calyx

CALYX & COROLLA

Parts of corolla

Re-curved beaked keel

Wings

Keels

Standard

GROUNDNUT FLOWER AND ITS PARTS Calyx (Fig. 14.4, 14.5) There are five pale-green sepals. They form a narrow sparsely pubescent hypanthium 4 to 6 cm. long. The calyx has five lobes; in two groups of one and four. The single sepal is juxtaposed (placed side by side) to the keel while the other four are fused except at their tips. Corolla (Fig. 14.4, 14.6) There are five petals, viz., the standard and the two lateral wings are free and the remaining two petals are fused to form a keel. The standard petal has a range of colours from yellow to orange to dark orange or garnet, and in rare cases, it is white or creamy white. It has a central area called the standard crescent, which has darker lines (or markings) radiating form the base to the periphery of the standard in most cultivars. The wings are generally yellow and wrap around the keel. The

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keel is pale yellow, and closely wraps around the stamens and the upper parts of the style and stigma.

Fig. 14.5

4 sepals 1 sepal Androecium (Fig. 14.14.6, 14.7). There are 10 monadelphous stamens of which two are staminodes (sterile) The calyx has five lobes; in two groups of one and four. represented only by They form a narrow sparsely pubescent hypanthium filaments. The remaining eight are dimorphic. Of these, four are with globose, dorsi-fixed and monothecous anthers, alternating with four having Gynoecium and androecium taken out of keels adnate, notrorse, Reproductive organs oblong anthers, three of which are bithecous and one, opposite the standard, monothecous. The basal two-third length of the filaments is fused. The filaments of the globose anthers are initially shorter than those of the oblong ones, but they Keels elongate and become equal to or longer than them a few hours after pollination. Four anthers are oblong and four globose, arranged alternately.

Gynoecium (Fig. 14.6, 14.7). The ovary is situated at the base of the hypanthium; it is superior, about 1.5 mm long, and normally has two to four ovules, occasionally five, and rarely six. The style is long and filiform with two bends; the first bend is closed to the upper end of the hypanthium, and the second one occurs along with the bend in the keel petal. The style has upward-slanting hairs on its distal portion. The stigma is club-shaped and usually on level with, or slightly above, the anthers. Anthesis : Flowering begins 17-35 days after seedling emergence, depending on the cultivar and environmental conditions. Low temperatures generally delay flowering. The flowering pattern varies among and within the botanical varieties. Generally the valencias flower before the other types and have short time of

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REPRODUCTIVE ORGANS

Stigma

Fig. 14.7 Oblong anthers (4)

Keel

Staminal column

Globular anthers (4)

Non-functional anthers (2)

Androecium (diadelphous)

Gynoecium

REPRODUCTIVE ORGANS OF GROUNDNUT flowering. The spanish types also flower early, but the first flowering peak may be broader than that in the valencias and some cultivars have multiple peaks. The virginia types take more time than the other two types to start flowering and have multiple flowering peaks.

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Fig. 14.8

Flowers are born in the axil of leaf

Aerial Portion Peg

PLANT WITHOUT ROOTS

Axil of leaf

Under ground

Peg

Pegs

Pods Pods of groundnut being uprooted from the soil

The flower bud is 6-10 mm long 24 h before anthesis and, during the day, the hypanthium elongates slowly and the bud attains a length of 10-20 mm. During

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the night, elongation of the hypanthium is faster. The flower reaches maximum length of 50-70 mm at the time of anthesis. Flower opening is normally at sunrise, but may be delayed by low temperatures. Anthers may dehisce 7-8 h before flowers open in some genotypes; in others they may not do so even at flower opening. Stigma becomes receptive about 24 h before anthesis and its receptivity persists for about 12 hours after anthesis. Pollen grains are smooth, oval and sticky. Fertilization occurs about 6 h after pollination. Pod formation (Fig. 14.1, 14.8, Fig. 14.9 14.9, 14.11). After fertilization, the stalk of the ovary elongates to form what is known as the gynophore (needle or peg), which curves downwards and enters the soil pushing the ovary below the ground where the pod is developed. The pods are fibrous, each having 1 to 3 seeds.Mature Groundnut Fruits Mode of Pollination The groundnut flowers are cleistogamous; therefore, it is essentially a selfpollinated crop. The extent of natural cross pollination is very small. Emasculation (Fig. 14.10). Method 1 The emasculation is generally performed in the evening. Usually one flower bud from each inflorescence which is near to main stem is selected. In order to get more percentage of hybrid seed, the plant should be young and in the early stage of flowering. The sepal which is in front of keel is removed and the sepals on the side of standard are pushed down. Spread the petals apart and remove the stamens with care. After emasculation, the petals are placed back. Usually bagging in not necessary to protect the emasculated flower. The emasculated flowers are identified by attaching a small thread to the hypanthium and aluminum tag/foil around the hypanthium or emasculated flower.

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EMASCULATION AND POLLINATION IN GROUNDNUT Modified from Source: floral%20stock%20files/groundnut%20all/Artificial%20hybridisation%20of%20Bambara%20Gro

Fig. 14.10

1

2

13

3

4

5

6

7

8

9

10

11

12

14

15

16

Fig. 14.10…contd.

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Fig. 14.10…contd.

17

20

21

25 1. 2. 3. 4. 5. 6. 7.

19

18

23

22

26

27

24

28

EMASCULATION: Flowers at a good stage for emasculation. Notice that anthers are still closed Flower attached to peduncle. Each peduncle usually bears two flowers. The second flower was removed in this picture. Hold flower at base with left hand tweezers. Make sure not to bruise flower. Insert tip of right hand tweezers at base of keel petals Move tweezers to tip of flower splitting the keel petals Push tip of tweezers through middle of flag petal and split to the tip. Open flower and locate stamen and style with stigma

139

Fig. 14.10…contd. 8. Push style with left tip of tweezers to the left side of the flower to prevent damage 9 Hold accessible stamen with tweezers 10. Remove anthers from flower 11. Repeat procedure to get hold of remaining anthers 12. Open flower to check for hidden anthers 13. Remove anthers with tip of tweezers 14. Clean tip of right hand tweezers. Let flower go from left hand tweezers. Emasculation is finished. 15. POLLINATION: Get stamen and carpel from male partner. Make sure that anthers are freely shedding pollen. 16. Open flower with right hand tweezers exposing stigma. 17. Pollinate stigma with stamen and carpel from male partner held by left hand tweezers. 18. Pollinated stigma 19. Close flower with right hand tweezers leaving male organs at stigma. 20. Hybridization finished 21. Tag flower with thin copper wire. 22. Fix tag 23. Tagged flower 24. Successful fertilization can be determined if ovaries fold back at flower base, pointing towards glandular apex. Unfertilized flowers fall of without folding back. 25. Fertilized ovaries can stay at this stage for several days, during which the peduncle lengthens to bring ovaries to or below soil surface. 26. After about 10-14 days pod development starts. 27. Left photo taken on 10.10.2001, Right photo taken on 14.11.2001. This is a typical example of paused pod development. In the same time period other pods developed to a size of ca. 15 mm. Despite above soil development of pods is possible, underground pods are generally preferred in development. 28. Pod at about 18mm size.

Method 2 In this, the flower buds two thirds down from the tip are cut to remove the standard and a small portion of the wing petals. The anthers are then removed and a folded piece of drinking straw is inserted over the emasculated flower.

140

Pollination (Fig. 14.10). Pollination is done on the morning of the day following emasculation. The pollens are collected from the desired male parent and pollens are applied with a small camel hair brush on the stigma. Fig. 14.11 Peg Formation After fertilization, the stalk of the ovary elongates and curves downward pushing the ovary below the ground where the pods containing the nuts develop. Extent of cross pollination The groundnut is self-fertilized, although bees do visit the flowers and there may be occasional cross-pollination.

Pod at physiological maturity

Wing

Standard

Fig. 14.12

Anther Sterile anther

Stigma Keel Filament Style

Ovary

Staminal tube

Calyx tube Calyx tube

Ovule

Longitudinal Section of Groundnut flower

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Floral Biology of Rapeseed and Mustard Family Genus Species

: : :

Crucifuae Brassica campestris, napus, juncea, rapa, nigra, carinata

Chromosome numbers, genome structure etc.: Species B. nigra Kotch B. oleracea L. B. rapa L.

Chromosome No. (2n) 16 18 20

B. tournifortii Gouan Eruca sativa B. alba Rab. B. carinata B. juncea Czern B. napus

20 22 24 34 36 38

Mode of reproduction CROSS POLLINATED CROSS POLLINATED Brown sarson Lotni type…….CROSS POLLINATED Tora type……. SELF POLLINATED Toria……………CROSS POLLINATED Yellow sarson…SELF POLLINATED SELF POLLINATED SELF POLLINATED SELF POLLINATED OSELF POLLINATED OSELF POLLINATED SELF POLLINATED and CROSS POLLINATED

142

Fig. 15.1. Crop view of Brassica species Rapeseed and Mustard (Fig. 15.1) are most important oil seed crops in India. Next to groundnut, they are important edible oil seed crops. Most of edible oils are obtained from rapeseed and mustard. Rapeseed & mustard play an important role in oil seed economy in India. They are considered as ‘cash crops’. Brassica juncea was originated in China and from there it was introduced into North Eastern India. From India it has spread into Afghanistan via Punjab and adjoining parts of India and Pakistan is the place of origin of brown sarson (Brassica Campestris) The crop is grown both in subtropical and tropical countries. In Asia it is chiefly grown in China, India and Pakistan. In India, Brassica crop is widely cultivated in Uttar Pradesh, Rajasthan, Madhya Pradesh, Assam, Bihar, Orissa, Haryana, Punjab, Gujarat and West Bengal. Inflorescence (Fig. 15.3) The inflorescence is an elongated raceme, borne terminally on the main stem and branches, usually carrying bright yellow flower, although colours can vary from orange to very pale yellow. The number of flowers is influenced by climate, cultural techniques and variety and can range from dozen to twice this, occasionally more. Rapeseed produces many more flowers than pod and under controlled conditions it was found that only 68% of flowers became pods, the rest were shed indicating that flower shedding is a problem.

143

Stamens (tetradynamous) stigma Petals(4) (Cruciform)

stamen ovary

Sepals (4) Outer whorl Inner whorl

FLOWER claw veins anther limb

stamen ANDROECIUM

COROLLA

(TETRADYNAMOUS)

(CRUCIFORM) (open out petals)

stigma False septum calyx

Inner whorl

style bicarpellary syncarpous ovary

Outer whorl

sepal

Sepals in two whorls

CALYX

GYNOECIUM

Fig. 15.2. FLORAL MORPHOLOGY OF BRASSICA FLOWER The anthers are placed lower than the stigmas at bud stage but prior to flower opening, the filaments elongate and carry the anthers upward so that they are as high as or above the stigma (Fig. 15.9). Vernalization, i.e., low temperature in the

144

Youngest flower bud

Youngest flower bud

Opened white flowers

Opened white flowers

Developing pods

Fig. 15.3

B. napus

B. juncea

early vegetative stage is a major factor influencing flower bud development and therefore seed yields in winter. Anthesis The flower begins to open before 8 a.m. and continue to open until about noon. Flowers remain open for 3-4 days after which the petals, sepals and stamens are shed. Fruit The fruit is a long narrow pod, Siliqua, 5-10cm in length (Fig. 15.11) consisting of 2 carpels separated by false septum called replum (Fig. 15.2) which shatters when mature. The pods contain 15-40 small, round seeds. Seed is generally matured 3040 days after fertilization. Mode of Pollination See table 1 on page 142

145

Petals

Corolla

Calyx Sepals

Androecium

Gynoecium

Peduncle Fig. 15.4. THE FLOWER

Fig. 15.5

146

Cruciform a b

Claw

c

Limb e

d

a = flower with yellow petals, b = flower with vain pattern petals, c = flower with white petals, d = flower without petals, e = detached petals from the flower

Fig. 15.6

147

Stigma

Style

Ovary

Six stamens (4+2) in two whorls

Stigma

Stamens

Style

Corolla is absent

Fig. 15.7

Sepal

Peduncle

B. juncea Apetalous Flower

148

Fig. 15.8

Comparative growth of androecium and gynoecium

A

B

C

D

The anthers are lower than the stigmas at bud stage but prior to flower opening, the filament elongate and carry the anthers upward so that they are as high as or above the stigma

A: immature bud stage showing shorter stamen than style, B: Style elongates to reach the level of stigma , C: Anther above the level of stigma and Fig. 15.9 D: Elongation of ovary after fertilization.

149

Emasculation, Crossing and Selfing Techniques Flowers are emasculated in the evening and pollinated the next morning (Fig. 15.14, 15.15) . Flower buds that will open next day are selected and the remainder of the buds and flowers and flowering branches are removed. The petals as well as stamens of the selected buds are removed with a pair of tweezers and the emasculated flowers are bagged. Ripe anthers are collected next morning and pollination is made by dusting pollens from the ripened anthers over the stigma. After pollination, the flowers are again bagged. Flowers to be selfed should be bagged before they open to avoid natural cross pollination. Bag should be of such size as to allow lengthening of flowers. In rape, the pollen grains are reported to remain viable for seven days while the stigma is receptive from three days prior to opening of flowers to 3 days after opening. Insects also enhance pollination, leading to cross pollination (Fig. 15.10).

Fig. 15.10

150

BRASSICACEAE (CRUCIFERAE) Mustard Family Herbs with odorous, water juice, annuals, biennials, and perennials Leaves alternate, simple, often dissected, stipules absent Flowers bisexual, actinomorphic, usually in racemes Androecium of 6 stamens, 4 long and 2 short Corolla of 4 petals arranged in a cross, hence Cruciferae Fruit a silique (long) or a silicle (short) - modified capsule dehiscing by 2 lateral valves having a central septum (replum)

350 genera, 3000 species Brassicaceae is a sharply defined and readibly recognized family, however, genera are illdefined Economic importance Brassica - brussel sprouts, broccoli, mustard, cabbage, cauliflower, turnips, kohlrabi, kale Raphanus -radish some ornamentals and weeds (escaped Brassica) Diagnostic characteristics: herbs, infl. a raceme, stamens 4+2, fruit a silicle or silique

Fig. 15.11

151

Eruca sativa (Taramira)

Fig. 15.12

Calyx

Fig. 15.13

152

POLLEN COLLECTION

Fig. 15.14

Emasculated buds

Fig. 15.15

153

Inflorescence is raceme, i.e. infinite type of inflorescence in which older flowers are at the bottom. Fig. 15.17

petal

Varying degree of incision

petal Fig. 15.16

Flowers are regular, cruciform, bisexual, complete and hypogynous (Fig. 15.4, 15.17). Calyx comprises of 4 sepals in two whorls of two sepals in each whorl in polysepalous condition (Fig. 15.5). Corolla consists of 4 petals (Fig. 15.4, 15.6); the petals bifurcated with varying degree of incision (Fig. 15.16). They are generally yellow in colour. Petals are cruciform with distinct limb and claw (Fig. 15.6). Androecium comprises 6 stamens arranged in two whorls in tetradynamous condition (Fig. 15.2, 15.7). The two outer stamens are short and four inner are long. The immature stamens are always below the stigma and after maturity anthers split longitudinally and shed their pollens. Gynoecium is bicarpellary in syncarpous condition (Fig. 15. 2, 15.7). Ovary becomes two selled owing to the development of a false septum called, the replum. Anthesis and mode of pollination: (Fig. 15.9). Opening of flowers start from 8.a.m. and continues up to mid day. There is an increase in style length before the bud opens. Just prior to bud opening the filaments elongate and carry the anthers at the level of stigma. Anthers start dehiscing downwardly from the apex as soon as the flower opens. The flower remains opened for three to four days, fading gradually on successive days. On 5th and 6th day the petals and sepals fall away. By this time fertilized ovary also increases in length. Pollen grains remain viable for 7 days after dehiscence. Stigma becomes receptive 3 days prior to the opening of the flower and remains receptive 3 days after the opening of the flower. In B. compestris, yellow sarson (turnip rape) and toria (Indian rape) are selfpollinated, although 5-12% of outcrossing may occur. In yellow sarson. The brown sarson and toria of lotni type are cross pollinated because of self sterility.

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Floral Biology of Sunflower

Family: Genus: Species: Origin:

Compositae Helianthus annuus

Other Species:

tuberosus petiolaris

Fig. 16.1

Native of United States and Mexico

Chromosome No. :

Basic chromosome No, x=17 Helianthus annuus : 2n = 2x = 34 Helianthus tuberosus: 2n = 6x = 102 Helianthus petiolaris: 2n = 2x = 34 Sunflower was introduced in India as an oilseed crop for the first time in 1969. Sunflower is a new oilseed crop. But it was grown in India as an ornamental crop since ancient times. Sunflower is a native of United States and Mexico from where it was introduced into Spain by early explorers and merchants. In the nineteenth century, the cultivation of sunflower as an oilseed crop began in Soviet Union and the majority of the present day varieties grown all over world trace back their origin to USSR. The cultivated sunflower for oil purpose is an annual having a single un-branched stem terminating in a large golden head, the capitulum (Fig. 16.1). It exhibits wide range of variation for morphological characteristics. Plant height varies from 50 to over 500 cm with stem diameter ranging from 1 to 10 cm. Plant height depends on number and length of internodes. Sparse hairs are seen all along the stem. The elongation of stem ceases

155

after ray floret opening in the inflorescence. Wild species and majority of the restorer lines are branching types (Fig. 16.6), each branch originating from the leaf axil and terminating with a small-sized inflorescence. Four different branching forms have been observed. The plant has a strong central root called tap-root which penetrates soil to a depth of 150 to 300 cm. The lateral roots spread widely from 60 to 150 cm. In cultivated sunflower, generally 20 to 25 leaves are borne on the stem. Leaves are produced in opposite-alternate pairs and exhibit wide differences for colour, size, shape, margin, surface, hairiness, apex and petiole length. It can be cultivated in any season viz. kharif, rabi and summer throughout India. Sunflower seed derives almost 80% of its economic value from oil, while defatted meal is the main by product after oil extraction. The meal contains 40-45% highly digestible protein suitable for human food or livestock feed. The major sunflower producing countries of the world are the Soviet Union, USA, Argentina, Romania, Spains, Yugoslavia, Turkey and South America. In India sunflower is grown in Andhra Pradesh, Bihar, Karnataka, Maharashtra, Orrisa, Rajasthan, Tamil Nadu and U.P. Maharashtra and Karnataka are two major producers. Floral Biology Inflorescence (Fig. 16.3, 16.4, 16.5) The inflorescence is a capitulum (Fig. 16.1) or head which varies in size and shape. Most of the cultivated varieties in India show a range of 10 to 35 cm for head diameter. The leaves are heliotropic which increases the photosynthetic efficiency, until flowering inflorescence is also heliotropic after that it remains fixed facing eastwards. The shape of head may be concave, convex or flat attached to main stem at varying angles. Involucral bracts (phyllaries) (Fig. 16.3) which vary in size and shape surround the head. Sunflower head consists of two types of flowers. The outer flowers, which are usually yellow, are ray florets. These flowers are sterile but do attract insect pollinators. The inner disc florets, which are hermaphrodite and fertile, are arranged in arcs radiating from the centre of the head. The flowering process begins with unfolding of outer ray florets. The outer whorl of disc flowers open first proceeding gradually towards the centre of the head. In general, 2 to 4 whorls open daily and complete flowering occurs within a head in 5-8 days. The flowering period will be longer if heads are large or weather is cool and cloudy. Anthesis (Fig. 16.2) takes place in the morning hours between 06000800 hrs on warm sunny days. Anthesis is delayed if weather is cool, cloudy or wet. The sunflower is protandrous. Pollen is dehisced within the anther tube. As the style elongates and pushes up through the anther tube, the pollen is mechanically forced out. The style continues to elongate until the stigmas emerge from the anther tube and the lobes separate, exposing their pollen receptive surfaces. Pollination and fertilization occurs when the spiny viable pollen is transferred to stigmatic surface. There is a limited role of wind in pollen transfer. Cross pollination is favoured by insects, in particular, honey bees.

156

Fig. 16.2

Progressive stages of anthesis (Disc florets)

1

3

5

2

4

6

The outer whorl of disc flowers open first proceeding gradually towards the centre of the head. In general, 2 to 4 whorls open daily and complete flowering occurs within a head in 5-8 days

157

1 Involucral bracts (phyllaries) Involucral bracts (phyllaries)

Ray florets are uncoiled from the centre first

Ray florets (folded)

The inner disc florets, which are hermaphrodite and fertile, are arranged in arcs radiating from the centre of the head.

3 Ray florets almost opened uncovering the disc florets

Ray florets (folded)

2

Capitulum Disc florets Completely opened ray florets

MATURE CAPITULUM

Bracts

Mature seeds Ready to harvest

achne

Side view of Capitulum Ray florets

Anthers forming A tubular structure

Tubular sepals

Disc florets

Fig. 16.3

Each disc floret consists of inferior ovary, two pappus scales (modified sepals) and a tubular corolla formed by the fusion of five petals, except at the tip. Five anthers are united to form a tube with separate filaments attached to the base of corolla tube. Inside the anther tube is the style, terminating in a divided stigma.

158

When the flower is fully developed, the style is elongated and the bifid stigma curls outward.

Fig. 16.4

Tubular sepals

Sepals free at the top

Towards centre of capitulum

Progressive Stages of Stigma emergence

Towards Periphery of capitulum

CLUSTER OF DISC FLORETS

bifid stigma curls outward

ovary

Pappus

corolla tube

(second is broken)

anthers are united

Disc Floret Showing Receptive Bi-fid Stigma The individual disc flowers are effectively protandrous and the positioning of stigma above the anthers make self pollination difficult. The disc flowers are perfect with petals and five anthers that are united in separate tubes. The disc flowers are arranged in concentric circles radiating from centre of the head. These are hermaphrodite and fertile. Each disc floret is made up of inferior ovary, two pappus, which are modified sepals and a tubular corolla formed by fusion of petals except at the tip. The five anthers are also fused to form a tube with filaments attached independently at the base of corolla tube. The style is inside the anther tube with stigma divided at the tip. When the flower is fully developed, the style elongates and the bifid stigma curls outward.

159

Ray florets are male and female sterile i.e. they are normally asexual but some may produce pollen. The ray flowers open first and flowering then proceeds from periphery to the centre of the head at the rate of four rows per day.

Tubular sepals

Sepals free at the top achne

achne Pappus

Pappus

Pappus attachment at physiological maturity of seed

1

2

3

4

5

6

7

8

9

Developmental DevelopmentalStages Stagesof ofDisc DiscFlorets Florets Fig. 16.5

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10

Fruit : (Fig. 16. 3, 16. 5). Sunflower seed (achne) comprise pericarp (seed coat or hull) derived from the ovary wall and the kernel which is mostly embryo. The pericarp comprises between 20 per cent (oil types) and 40 per cent (confectionery types) of seed weight. Seed exhibits a wide range of variation for seed weight, seed coat colour and size. Total seed yield in a head is the product of total number of seeds and seed weight. The fruit is compressed, flat, oblong with top truncate and base pointed giving a roughly diamond shape. Colour of seed may be white, black or black with strips. Seed is Dicotyledonus and exalbuminous. Anthesis : (Fig. 16.2). Opening of all florets on a single heads is usually completed in 5-10 days but if individual florets are not quickly pollinated they can remain receptive for 14 days with a greatly reduced possibility of being fertilized. Flowering within a crop of hybrid sunflower is remarkably uniform, with 80-90 per cent of heads opening within 3-4 days. Pollination : (Fig. 16.6). Sunflower is a highly cross pollinated plant. The individual disc flowers are effectively protandrous and the positioning of the stigma above the anthers make self-pollination difficult. A genetically controlled system of self-incompatibility in certain lines prevents the pollen from penetrating the styles and carrying at fertilization. Sunflower is pollinated mostly by insects. Bees are frequent visitors to flowers on warm, sunny days. Little pollination is accomplished by wind drops on the leaves or on the ground in clumps of five or more grains. Self pollination is achieved by placing a bag over the head before anthesis or anther dehiscence. The amount of seed set depends on the degree of self compatibility of the lines and type of bag used. Cloth bags have been found to be most efficient among several kinds tested for effecting self-fertilization of sunflower. Seed set was increased considerably when heads were pollinated by brushing with cotton batting. Pollination in field nurseries can be effected simply by rubbing heads from the two parents against each other. The pollinated head is maintained in isolation by re-bagging. Emasculation Emasculation of the female parent can be performed with forceps. Workers have individual preferences for the type of forceps. Some prefer a fine, sharp-pointed surgical type; others use a somewhat larger, coarser type with points about 3 mm wide. A disinfectant, such as ethanol is used for sterilizing the forceps between emasculations to prevent unwanted cross pollination. The ray flowers and bracts usually are removed before emasculation to make the flowers on the disc more accessible and eliminate a large surface area on which pollen could lodge. The flowers opening prior to the day of emasculations can be removed from their ovaries by a simple sideways pulling motion with the thumb

161

Fig. 16.6

A-Line

B-Line

R-Line

Pollen Collection

Pollination

Selfing

R-Line

162

and forefinger. The Fig. 16.7 ideal time to emasculate is in the period when the anther tube is extended sufficiently to be grasped with the forceps but the pollen has not yet dehisced. In practice however, because of the short duration of this period the anther tube often is removed after dehiscence, but before the stigma has grown for enough into it to be THE CAPITULUM injured or for the stigmatic lobes to separate when the tube is removed. Free pollen on the outside of the stigma lobes must be blown off. Undeveloped central florets are removed, usually by cutting them off with a knife just above the ovaries. A few flowers closely adjacent to those emasculated cannot be cut off with a knife without danger of damaging the emasculated flowers. These can be removed with forceps. Pollen Viability It is best to use the pollen shortly after collection. Some studies [Arnoldova (1926)], indicate that pollen can be stored for a year, but other workers have found that viability is lost within a month whether the pollen is stored at room temperature or is refrigerated. Stigma Receptivity The stigma normally remains receptive for 3 to 5 days, although its viability can be preserved up to 17 days under field conditions. Stigmas of flowers which are not fertilized continue growth for several days to form a coil which will allow the stigmatic surface to contact pollen adhering to outer surface of the stigma lobes. Hybrid Seed Production Hybrid seed is generally produced using CGMS system, i.e. A-, B-, and R-lines (Fig. 16.6). R-lines are generally branched and have many small heads. B-line is isogenic to A-line. R-line has high sca with A-line.

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Floral Biology of Linseed Family : Genus : Species : Chromosome no. : Origin : Common name:

Linaceae Linum usitatissimum 2n=30 South-Western Asia and Mediterranean area of Europe Alsi

Normally Fig. 17.1 Linseed (Fig. 17.1, 17.2) is a self pollinated crop although 0.3% to 2% natural crossing has been observed. The amount varies with the variety, season, and kind and number of insects present. Linseed Linseed contains a good percentage of The Crop oil and it varies from 35 to 45%. It is also an important source of industrial oil in the country. Linseed oil is used for cooking purpose in various parts of India. Its oil is an excellent drying oil which is extensively used for preparation of paints, varnishes, printing ink, soap, patent leather and water proof fabrics. Oil-cake is a good cattle feed for mulch animals

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and also a good manure. Oil-Cake contains 36 per cent protein out of which 85 per cent is digestible. It contains 5.5 per cent N, 1.4-1.5 per cent P2O5, and 1.2-1.3 per cent K2O. It produces fiber of good quality and used in making paper and plastics. Fiber is used for the manufacture of linen goods such as twine, canvas, suiting and shirting, water resistant pipes etc. The remaining material after fiber extraction can be utilized as pulp for manufacturing straw boards, writing papers and parchment paper. The stalk is used for fuel. The fiber also forms a cheap source of cellulose for the development of artificial silk. Fig. 17.2

Fig. 17.3

Linseed is a winter annual plant with tap root which is slender and possesses numerous small lateral roots (Fig. 17.2). The stem is woody and branched. Its height varies from variety to variety (about 80-90 cm tall). Leaves are small, alternate, entire, stipulated, linear to lanceolate and blunt at the apex. The leaf colour ranges from fresh green to bluish green. Floral Biology Inflorescence is usually cymose i.e. the flowers are born in cymes. Flower: (Fig. 17.3, 17.4, 17.8) The flowers are pentamarous i.e. 5 free persistent sepals, 5 free petals, 5 stamens and gynoecium with 5 slender styles are present (Fig. 17.8).

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Calyx: (Fig.17.3, 17.5) The Sepals are 5 in number- ovate, ciliate, three- nerved, acuminate and persistent.

Corolla: (Fig.17.4, 17.7) Petals are 5 in number and their colour varies from variety to variety. These color variations are white with blue tinge, pale-blue, deep-blue, violet, deep-violet, softbluish violet, purple or pink, bluish-pink. Pink corolla is not observed in India and is found in European materials. The petals vary in shape from sub-linear to broad in which the length and breadth are equal. They fall into 2 classes- Narrow and Broad petals. In fully opened flowers with narrow petals, a certain amount of space is left between the petals, but when the petals are broad, they overlap. The petals remain twisted in bud and fall off early. They remain twisted at the base into hypogynous discs on which are 5 glands representing perhaps an absorptive whorl of stamensopposite the base of the petals.

Fig. 17.4

Petals (5)

Reproductive organs

Androecium: (Fig. 17.4, 17.9) The various parts of the stamens including pollen, exhibit wide coloured range. The filaments are white or white with various shades of blue or purple. All shades of colour from pale blue, bright blue to purple are present. The anthers are either white or white with a blue line or blue. Pollen grains are blue, yellow or white. This difference

166

Calyx Fig. 17.5

is accentuated by the colour of the anther. The blue pollen which occurs in European forms is not observed in Indian linseeds. Gynoecium: (Fig. 17.4, 17.9).The ovary is 5celled; each locule more or less completely divided Free into two by a false septum, resulting in a tenroomed capsule, each containing one ovule, developing into one embryo. The ovules are pendulous, anatropous Free Fig. 17.6 Twisted Twisted and are situated in the inner angle of the locules, Twisted Aestivation of calyx two in each. The five at Early Stage Only long styles are free to the base, with loose union at the stigmatic ends. The styles are white which also show variations of blue or purple shades. The stigma remains receptive for a period of 2

167

hours before and 5 to 6 hours after opening of the flower i.e. stigma receptivity is up to 8 hours.

Fig. 17.7

Linseed

Corolla Twisted Aestivation Fruit: (Fig. 17.10) The seed is oval and pointed at one end. Its length varies between 4 - 6mm and breadth between 2 - 3mm. The seed surface is smooth and generally shining, but in some varieties it may be rather dull. The capsule possesses five chambers, formed from five carpel which are then incompletely halved by a false septum, resulting into a tenroomed capsule each with one seed. Thus we may expect ten seeds in one capsule. Anthesis When the petals become visible, the anthers are still short and immature. On clear days, the flower opens and the pollen is shed shortly after sunrise. The flower is fully open by 7 a.m. and the petals falls before noon. The linseed flower has 5 anthers and a pistil with five slender styles. Linseed is normally self- pollinated crop although 0.32% natural crossing has been observed. The maximum natural cross- pollination is found in varieties with open disc-form flower and least in the varieties with tubular flowers. The plants usually blossom over a long period.

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Pentamarous Flower Fig. 17.8

Five Sepals Five Petals Five Styles Five stamens Five Carpels Emasculation and pollination The linseed flowers show a cone of flower on the after-noon preceding opening and emasculation are made late the afternoon or early evening. The cone of petal is removed by pulling gently with the thumb and index finger. The one or two sepals are rolled back and held down while the five anthers are removed with the point of a pencil or fine pointed tweezers. Care must be exercised to prevent injury to the stigma or it will dry out rapidly. The emasculated flower may be marked by tying tags. The emasculated flowers need not be bagged, because they do not attract insects. Pollination is made the next morning before 8 a.m. Delay in pollination may result in a poor seed set because the pollen dries out rapidly. Petals are removed to supply the pollen, and their anthers are brushed lightly over the stigma of the emasculated flower. One male flower will pollinate two or three emasculated flowers. About 5-7 flowers open on a plant each day during the full gloom period. With careful emasculation, correct timing of pollination and good weather, a high percentage of flower will set seed with an average of 5-7 seeds per boll. The linseed plant usually blooms over a long period of time. According to another study, the flowers open in the early morning and in all such buds the unfolded corolla is visible the evening before. When the corolla becomes visible,

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Fig. 17.9

filaments

Intact flower

One locule is 2-roomed = one cell

Stigma (5)

anthers

Reproductive Organs (fully opened)

ovary

ovule

T.S. of Ovary Flower with one petal removed

Reproductive organs

Gynoecium removed

Reproductive Organs (opened)

Androecium & Gynoecium Stigma (5)

Stigma (5)

Styles (5)

ovary ovary

ovary T.S. of Ovary

Gynoecium (Linseed)

Gynoecium

REPRODUCTIVE ORGANS OF LINSEED the filaments are still short and unbursted anthers stand well below the slightly twisted stigma. Further, the rapid growth of the filament soon brings the anther to the same level as the stigmas and this is the position when opening begins. According to these

170

authors the time of opening of flowers depends on the temperature and humidity. On warm mornings the flower open very early, while on cold mornings the process is delayed. According to another study the flowers open fully by 8 a.m. in the winter months. The stigma in the bud stage protrudes over the anther lobes but as the bud expends and the petals begin to unfold, the anthers gradually overtake the stigma and when the flower is in full bloom, the anthers surround or envelope the stigma completely. Dehiscence of the anthers occurs before the opening of the flower is complete. Thus the chances of natural crossing are considerably reduced. Seed Production Linum usitatissimum is self- fertilized. Separation from other crops of the same kind by a barrier or a gap of 3 meters is needed to prevent mixture at harvest. Where the cultivars to be grown for seed are of different kinds a greater distance should be provided.

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Fig. 17.10

Floral Biology of Lentil Genus: Species: Family: Sub family: Scientific name: Local name: Chromosome No.

Lens culinaris Leguminosae Papilionaceae Lens culinaris Masur 2n=2x=14

‘Lens’ originates from the Latin word meaning disc-shape seed (Fig. 18.7). It is a small genus comprising only six recognized species namely L. montbretii, L. ervoides, L. nigricans. L. orientalis, L. culinaris CROP VIEW and L. odomensis. L. culinaris is the only cultivated species found in Lentil. Lens culinasis (Fig. 18.1) is divided into two subspecies: 1. Macrosperma: found mainly in Mediterranean region. The seeds are large (6-9 Fig. 18.1 mm), have yellow cotyledons and have little or no pigmentation in flower or vegetative structure.

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2. Microsperma: Found mainly in Indian subcontinent. Smaller seed (2-6 mm) with orange or yellow cotyledons. It has smaller convex pods, leaf and leaflets.

Wings

Standard Sepals Standard

Keels Sep als

Flowers in pair Peduncle

Peduncle

Fig. 18.2

In India Lentil is cultivated in mid October to early November. It is nutritious and is mainly consumed in the form of dal and as an ingredient in soups. It is also used in textile and printing industries and young plants as fodder. The lentil seed contains 12.4% moisture 0.7% fat , 59.7% Carbohydrate, 25.1% Protein and 2.1 % ash. The plant is branched, sub-erect, slightly pubescent, annual, usually 15-75 cm tall. The roots may be much branched, shallow root system or slender tap root system or an intermediate form. The stem is square and ribbed with several basal branches. The leaves are alternate with 4-7 pairs of opposite of alternate, leaflets approx. 1.25 cm. long. Inflorescence

Keels

Standard

Wings

Sepals

Calyx and Corolla (Fig. 18. 6) Calyx It is an axillary raceme with 1-4 flowers; with a slender peduncle (Fig. 18.4). Rachis ends into a Peduncle filiform apex, bracts are absent and Fig. 18.3. Flower pedicles are short. Calyx is companulate; tube is about 1.5 mm long, 5-lobed, narrow, sub-equal, about 3 mm long. Corolla may be white, pink, purple or red in colour. Standard petal is hood shaped, broadly obovate, small, about 5x4 mm, clawed, obcordate and mucronate at top. Wings are oblong to

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obovate about 4.0 x 1.5 mm with a long claw, adhering to the keel, 4.0 x 2 mm, entirely split dorsally, ventrally split near the base and clawed. Androecium: (Fig. 18. 5). Stamens are diadelphous (9+1), axillary stamen being free, gradually winged towards base. Staminal sheath is about 2.5 mm long. Anthers are basifixed, nearly spherical, about 0.2 mm in diameter, light yellow in colour.

Flower

Peduncle

Gynoecium: (Fig. 18. 5). Ovary is sub sessile, laterally compressed, about 3 mm long, sparsely pubescent, with 2-3 ovules. Styles are abruptly unturned, slightly flat, about 1-5 mm long, glabrous, but hairy along the inner lower surface of stigma. Stigma is spatulate, swollen, and glandular papillate. Axillary

Fig. 18.4. Branch

Anthers Staminal column

Sepal

Fruits: Pods are oblong, laterally compressed, bulging over the seeds, measuring 1.2 – 1.4 cm, rounded at base with a short beak at tip, glabrous, with 13 seeds.

Free stamen

Androecium

Fig. 18.5

Mode of pollination: It is a selfpollinated crop but cross pollination can also occur to little extent.

Stigma Style Hairs

Ovary

Gynoecium

Anthesis: Flowers begin to open at 8 a.m. to 10 a.m. and continue to do so till noon and remain open the whole of that night and the next day. It depends chiefly on temperature and humidity. Flowering: Lentil requires long days for flowering. It may start from 50th day. Flowers are born on axillary racemes as

1, 2 or 3 to 4 flowers per node. Seed: (Fig. 18. 7) Seeds are lens shaped, 4-8 mm in diameter. Co lour varies from light gray, brown to grayish black. Cotyledons are yellow to orange.

174

5 sub-equal sepals

Calyx

STANDARD

WINGS Fig. 18.6

COROLLA

KEELS 175

black

orange green

Disc/lens shaped pulse grains/seeds Fig. 18.7

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Floral Biology of Berseem Family: Leguminosae Genus: Trifolium Species: Alexandrium Chromosome no.-2n=16 Basic chromosome no. x=8.

Berseem (Fig. 19.1) is primarily grown as fodder crop in North India. It is a multi-cut crop and generally 4–6 cuts are taken. It grows very fast and provides fodder for a longer period. The fodder is succulent. Inflorescence: The berseem (Fig. 19.2) inflorescence is racemose and axillary. The flowers are complete, irregular, Fig. 19.1 zygomorphic and polypetalous (Fig. 19.3, 19.8).The flower head is round to oblong with yellowish colour. Colour may vary (Fig. 19.5). Calyx: Sepals are 5 in number and form a tube that terminates into 5 lobes or teeth. (Fig. 19.5, 19.8).

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Corolla: A standard petal, two wing petals and two keel petals unite at the base to form the corolla tube. The keel petals are straight, while standard and wings are narrow shaped. (Fig. 19.5, 19.8)

Younger flowers

Younger flowers

Older flowers

Older flowers

Axil of leaf

Florets

Fig. 19.2

INFLORESCENCE OF BERSEEM Androecium: (Fig. 19.4, 19.7 and 19.8) Stamens are 10 in number and in diadelphous condition. Gynoecium: (Fig. 19.4, 19.7 and 19.8). The gynoecium consists of monocarpellary ovary which is superior and unilocular. The style is incurved and stigma is oblique. Inside the corolla are 9 stamens and one stigma united into a sexual column. The number of ovules per ovary varies from 1 to 4. Single seed is formed in each floret. Anthesis and Mode of Pollination Berseem is generally a cross pollinated crop but self pollination do occur. The stage of bloom for optimum seed set appears to be when each flower is about half open. Stigma receptivity and pollen viability continue for 10 days with a gradual

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Wings and Keels enclosing reproductive organs

Calyx

Standard

Fig. 19.3

The flowers are complete, irregular, zygomorphic and polypetalous. The flower head is round to oblong with yellowish colour.

Reproductive organs

Staminal column

Fig. 19.4

Keel Calyx

Wings

Forceps

FLORET WITH STANDARD CUT AWAY

Sepals Standard

Fig. 19.5

Wings Keel

COROLLA

CALYX

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decrease each day. The fertilization takes place 28-32 hours after pollination. Berseem is mainly pollinated by bees. If pollinating insects are present it sets

WHITE

YELLOWISH ORANGE

CREAM

RED

RED

Fig. 19.6

WHITE

SHAPE AND COLOUR VARIATION OF BERSEEM FLOWER more than 70 seeds per head. Emasculation: Emasculation is done by removal of corolla. The underside of corolla is gripped with forceps at a point midway between the tips of calyx and the tip of the standard. The corolla tube and attached anthers are removed leaving the pistil intact. For self incompatible genotypes water is sprayed over stigma to kill pollens that may have dehisced prior to removal of corolla. Pollination: The most favorable stage of pollination is soon after flower opening. Pollination can be done at any time. Cross pollination of half open flowers results in maximum seed set.

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Anthers

Staminal Column Filament Stigma Style

REPRODUCTIVE ORGANS

REPRODUCTIVE ORGANS

Stigma Style

Anthers Filament Staminal Column

Fig. 19.7

ANDROECIUM AND GYNOECIUM Pollination can be done by two methods: Manual Pollination- The pollen is removed from the male plant by inserting a toothpick between standard and keel and applying downward pressure. This causes staminal column to strike and adhere to the toothpick. Pollen is then

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transferred from toothpick to female flowers. One collection of pollen usually pollinates 10-15 emasculated flowers.

wings stigma anthers 9 stamens

Keel

standard petal style Fig. 19.8

calyx Single stamen ovary ovule

BERSEEM FLOWER Natural but Controlled Hybridization- Cross pollination is done by growing two parents in a cage. Honeybees are introduced into cage to effect pollination and thus seeds obtained are hybrid. The bees may be washed before introducing them into cage. Washing causes the bursting of the pollen grains already sticking to the insect body, thereby making them ineffective.

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Floral Biology of Green Gram (Mungbean) Common Name: Moongbean / Mungbean (Green gram) Genus : Vigna Species : radiata Family : Leguminosae Chromosome no : 2n = 22,24 Origin : India Mungbean is herbaceous annual crop having a height from 30-100cm. Stem is diffuse and branched. It is green or purple and covered with dense hairs. The leaves are alternate, trifoliate with pointed leaflets subtended by small stipules. There are two stipules at the base of petiole. The leaves are dark green. Green gram is an excellent source of high quality protein. It contains about 25% protein. Mung is also used as manuring crop. Being a leguminous crop, it has the capacity to fix the atmosphere nitrogen. It also helps in preventing soil erosion. Mung is cultivated in India, Burma, Ceylon, Pakistan, China, Fiji, Queens land of Africa. In India, mung is grown in almost all the states. The important moong growing states are Orrisa, Maharashtra, Andhra Pardesh, Madhya Pardesh, Gujarat, Rajasthan & Bihar. FLORAL BIOLOGY Inflorescence: Small flowers are borne in capitate clusters on the ends of long hairy peduncles. Flower: The papilionaceous flowers are produced in short axillary racemes in clusters of 9-15. Calyx: The calyx comprises five sepals (Three large and free, two small and fused).

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Corolla: The corolla consists of five petals, papilionaceous (one standard, two wings and two keels united). The standard is wide and yellow. The keel is spirally coiled.

Main stem

Anthesis and Mode of Pollination Self-pollination is the rule. In about 50% of flower, the buds do not open (i.e. they are cleistogamous). The flowers open in the early morning, i.e. from 6-8 a.m. The dehiscence, however, takes place about 3-9 hours before the flower open.

Immature pods (Indeterminate growth)

Standard

Androecium: The androecium is diadelphous (9+1). Gynoecium: The gynoecium is monocarpellary with a superior, unilocular ovary. The style is twisted below the stigmatic surface. The stigma is hairy and the placentation is marginal.

Calyx

Wings

Mung bean Inflorescence (at green plant stage) Fertilized flower with corolla removed (developing pod) Calyx (gamosepalous) Standard (outer most petal) Main stem

Fertilized flower with corolla (developing pod) Unfertilized pods

Fig. 20.1

Undeveloped pod Mature pod

Emasculation and Pollination Dried flowers Fertilization in mungbeen occurs in the bud stage. The age of the bud appropriate for Mung bean Inflorescence emasculation is indicated (at plant maturity) by the appearance of the corolla just above the calyx. Immature anthers can easily be removed at this stage with a pair of forceps or with a needle. All the buds, except those which are to be

184

Opened calyx (gamosepalous) Closed calyx (gamosepalous)

Sepals (5)

Calyx

Fig. 20.2

Corolla: Wings

Corolla: Keels emasculated are removed. One day after emasculation, the anthers collected from newly opened flowers of the male parent are gently rubbed on the stigma of the emasculated flower. The petals of the emasculated flower are again brought to the normal position. SEED PRODUCTION Isolation: Mung bean is fully self-fertile and almost entirely self pollinated. Therefore isolation sufficient to prevent mixture at harvest is around 3 meters.

185

Fig. 20.3

Reproductive organs

Style anther

Stigma

Filament

Staminal column (9 fused anthers)

Reproductive organs

anther

Feathery Stigma

Style (typically curved)

Filament

Staminal column (9 fused anthers)

186

Pods

Mature pod (ready to harvest)

Locule containing seed

Mature open pod

Developing pod Mature Pod

Upper one third portion of mature pod

(bursting)

Hair

Grain

Locule

Fig. 20.4

187

Floral Biology of Barley Family: Genus : Species:

Gramineae Hordeum vulgare, distichum, irregulare.

Barley (Hordeum vulgare L.), one of the oldest of the cultivated cereals (Fig. 21.1), is widely grown in many climates of the world. Barley grows in the arid

CROP VIEW

Fig. 21.1

climates of the Sahara, the high plateaus of Tibet, and the tropical plains of India. Much of the barley grown in America is used for livestock feed with about 3035% being used for malt to enter into the production of beverages or foods. There are two theories regarding the origin of barley. According to first theory, centre of origin is Abyssinia as many diverse forms grow wild there. According to another theory, centre of origin is South Eastern Asia, particularly China, Tibet and Nepal. Barley, through the slow adaptive processes of nature, has developed a diversity of head and seed types, disease resistance, and quality characteristics. The genus Hordeum comprises about 24 species. These include diploid, tetraploid, and Hexaploid species.

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FLORAL BIOLOGY:

A

B

C

Fig. 21.2: 6-rowed (B, with awns and C-awns removed; and 2-rowed (A) barley Inflorescence (Fig. 21.2, 3, 4, 5): The barley inflorescence is a spike with three spikelets borne at each node. In most varieties the glumes are about one-half the length of the of lemma and terminate in a slender awn. In the six-row types each spikelet bears a flower (Fig. 13.1A and B), but in the two-row types only the center spikelet at each node bears a flower, the lateral spikelets being sterile or vestigal (Fig. 13.1C). Barley may be 6-rowed or 3-rowed. Three spikelets are borne on each node or joint of the rachis of a spike in a 6 row variety. Sexual parts are enclosed within glume, lemma and palea. Glumes are usually one half of the length of lemma and terminate in a slender awn. In six-rowed barley, each spikelet bears a flower, whereas in two row barley only the central spikelet develops a flower. The pistil bears a bifurcated feathery stigma. Three anthers are borne on long slender filaments. The flower, like those of wheat and oats, is enclosed within a lemma and palea (Fig. 13.1D). The pistil has a two-branched feathery stigma, and three anthers are borne on long slender filaments. Flowering begins in the central florets of the upper part of the spike and precedes both up and down the spike.

189

Fig. 21.3 As anthesis approaches, the lodicules at the base of the ovary swell, the flower opens, and the filaments elongate. The anthers dehisce as they emerge from the flower, and pollen is spilled upon the stigma. Slight cross-pollination may result if the flower opens before the anthers dehisce. During periods of high mean temperatures the anthers usually dehisce before the spike emerges from the boot. Fig. 21.4

Under these conditions cross-pollination seldom results. If artificial crosspollinations are made during periods of high mean temperatures, emasculation of the anther must be done early in the development of the spike because the pollen

190

ripens so early. Great care must be exercised to prevent the mutilation of the flower as it is very tender at this stage. High percentages of seed set may be obtained in barley if the emasculation and crossing procedures are carried out carefully. The barley crop is characterized by many variations in spike and awn characters. The six-row and two-row species are found. Many variations in the form of the hoods and awns occur. Some awnleted varieties have short awns on the center florets while the lateral florets are essentially awnless. Other varieties are almost completely awnless. Smooth awned varieties have been developed in which the awn is free of barbs. The hull adheres to the seed (Fig. 21.6) in most commercial varieties, but freethreshing hull-less or naked barleys also exist.

Fig. 21.5

anthers

palea lemma gynoecium SPIKELET OF BARLEY

Anthesis: Blooming starts in the ear of main shoot, followed by lateral shoots in the order of their emergence. Blooming first appears in the central spikelets and proceeds upward and downward gradually. Filaments elongate during anthesis and the anthers emerge out from the flower. Blooming is maximum between 6 am and 8 am and 3 pm and 5 pm. Anthers dehisce just after emergence and shed pollen on feathery stigma. Pollens lose their viability after two hours of the dehiscence. Stigma remains receptive for 2 days after anthesis Emasculation and pollination: Selfing : Natural selfing (self pollination) is a rule in barley. However, to ensure complete selfing, parchment paper bags are used. The spike is enclosed in the bag after

191

clipping the awns as soon as the spike emerges out of the boot. Tagging and libeling is done. Emasculation and Pollination: Emasculation: Select spike which is just emerging from the flag leaf. Remove central spikelet and retain two lateral spikelets per node or joint of the rachis of a spike in six-row varieties. Retain a total of 20 spikelets on ten nodes in a continuous series or in alternate position in the middle portion of the spike. Remove rest of the spikelets. Cut one-fourth portion from the top of each floret so that anthers become visible. Remove anthers with the help of fine pointed forceps. Cover the emasculated spike with a butter paper bag. Tag and label it.

Fig. 21.6

Pollination: After 2 or 3 days of emasculation, when stigma becomes feathery, pick up the spikes from the desired male parent which have just emerged from the flag leaf and cut the top one-third of the spikelet. Expose this ear to sunlight for 10-15 minutes, so that the anthers burst and pollen grains come out. Make slight tapping of the ear by hand, when pollen mass becomes visible. The pollen from this ear is dusted on all sides of the emasculated ear. Bag the pollinated spike. Barley is the major crop for feed and food in Northern areas of the world or at high elevations where its short growing season makes it more dependable than wheat or oats. In USA, it ranks 5th in the total production. Barley is the most important cereal grain for malting because of special physical and chemical properties. Isolation requirements: The crop is generally self fertilized. Usually not more than 0.15% cross pollination occurs. Pollination occurs while the head is in the boot in many varieties. An isolation of 3m all around the field is considered sufficient for maintaining varietal purity.

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Floral Biology of Cowpea

Family: Sub-Family: Tribe: Genus: Species: Local name: Common names: Related species: Chromosome No: Origin:

Leguminosae Papilionaceae. Phaseolas. Vigna Unguiculata (sinense) Gomatar, Barbati Black eye pea, catjang, chinapea, cowgram. V. luteola, V. marina, V. nilotica. 2n = 22 India.

Cowpea [ Vigna unguiculata (sinense) ](Fig. 22.1, 22.7) commonly known as lobia is used as a pulse, a fodder and green manure crop being rich in protein and containing many other nutrients. On dry weight basis cowpea grains Fig. 22.1 contain 23.4% protein, 1.8% fat and 60.3% carbohydrates. The crop gives such a vegetative growth and covers the ground so well that it checks the soil erosion in problem areas and later can be

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ploughed in as green manure. The cowpea is highly palatable, very nutritious, and relatively free of metabolites and other toxic principles. The seed particularly contains protein (90 % of which is water insoluble globulins and 10 % water soluble albumins), starch and vitamin. Wings

Developing pod after fertilization

Standard

Keels

Stigma

Standard Wings

Calyx

Keels Calyx

Anthers Staminal column Standard

Anthers

Wings

Calyx

Stigma

Keels

COWPEA FLOWER (OPENED FROM FRONT) PURPLE

Staminal column

YELLOW

WHITE

FLOWER COLOURS

Calyx

COWPEA FLOWER (OPENED FROM FRONT)

Fig. 22.2

PARTS OF COWPEA FLOWER Inflorescence It is composed of axillary racemes, with 2-12 flowers in each peduncle. Peduncle is 4-30 cm long, glabrescent at top, purplish at base. Rachis is glabrescent, tuberculate. Flower (Fig. 22.2, 22.5) It is bisexual, white, purple or pale violet. Fertile flowers are paired, laterally inserted into a tubercle. Bracts are one per flower and deciduous, about 3-4 mm long, fleshy at base, with ciliolate edge. The flower is complete with five sepals and five petals. The keel petal is straight, the standard petal is whitish to violet in colour, the stamens are 10 in numbers in which 9 are fused and 1 is free. The ovary is multilocular, the style is right angled and pubescent, stigma is oblique.

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The stigma becomes receptive one day before flower opening and remains receptive up to noon on the day of anthesis. Calyx (Fig. 22.3, 22.5) The calyx is composed of five sepals, which are gamosepalous. The two are large and three are small which makes 2+3 arrangement of sepals. COROLLA

Sepals

Gamosepalous

STANDARD

OPEN

STANDARD CLOSED

Wings: a close-up

Keels at flower bud stage

COROLLA Fig. 22.3 Keels in mature flower

CALYX AND COROLLA OF COWPEA FLOWER Corolla (Fig. 22.3, 22.5) The corolla is composed of five petals same as in case of chick pea. It consists of one large standard, two wings and two keels which are straight and purple in color. Androecium (Fig. 22.4, 22.5) The androecium is diadelphous (9+1). The nine stamens are fused and one is free. Gynoecium (Fig. 22.4, 22.5) The style is right angled and is hairy on inner side, with a terminal stigma; the ovary is monocarpellary with many ovules and is unilocular. .

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Fruit (Fig. 22.6, 22.7) The pods are 20 -30 cm long, cylindrical and slightly curved, with a thick beak slightly constricted between the seeds the seeds are variable in size and color.

Stigma

Free stamen

Free stamen

Reproductive Organs CLOSECLOSE-UP Anthers

Stigma & Style

Anthers Staminal column

Reproductive Organs

GYNOECIUM (Close-up)

Staminal column

Style

Style

Ovary

Hairy stylar top

Fig. 22.4 Stigma

Stigma

Hairy stylar top

GYNOECIUM

REPRODUCTIVE ORGANS Anthesis and Mode of Pollination Self-pollination is the rule. In about 50% of the flowers the buds do not open (i.e. they are cleistogamous). The flower opens in the early mornings, i.e. from 6 to 8 a.m., and may remain open till 11 a.m.. The dehiscence, however, takes place about 3 to9 hrs before the flower opens. Emasculation and Pollination Fertilization occurs in the bud stage. The age of the bud appropriate for emasculation is indicated by the appearance of the corolla just above the calyx. Immature anthers can easily be removed at this stage with a pair of forceps or with a needle. All the buds except those which are to be emasculated are removed. One day after emasculation the anthers collected from the newly opened flowers of the

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male parent are gently rubbed on the stigma of the emasculated flower. The petals of the emasculated flowers are again brought to the normal position. Another method of emasculation in cowpea requires removal of the entire corolla.

Wings

Standard

Gynoecium

Cut here Androecium

T.S. of flower

Parts of flower

Fig. 22.5

Then push a soda straw of optimum length over the pistil and pinch the upper end of soda straw with adhesive tape. Tagging is done as usual. Pollination: The mature anthers are collected in the next morning and pollination is done by gently rubbing ripe anthers against the stigma of female flowers. After applying the pollen, the soda straw should be replaced and left until fertilization is completed.

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Developing grain Ovary pealed off to see ovules (early stage)

Ovary pealed off to see ovules

Anothe half of seed

Half seed

Ovary pealed off to see ovules (close-up)

Mature pod

Fig. 22.6

Pod pealed off to see grains (Close-up o

Flower

SPECIAL FEATURE

Abortion Problem: There is high rate of abortion in cow pea, which can shed 70 to 80 % of its 100 to 500 flower buds prior to anthesis. Only 6 to 16% of the total flower buds produce mature fruits.

Pods

Fig. 22.7

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Floral Biology of Isabgol Family Scientific Name Common Name Chromosome No.

: : : :

Plantaginaceae Plantago ovata (Plantagoinsularis) Desert Indian wheat, Desert Plantain n=4, 2n=8

Plantago ovata forsk, commonly known as Isabgol (Desert Indian wheat) and commercially as blond phyllium, is an important medicinal plant. Name of Isabgol differs from place to place (see table). Uses The husk of the seed yields a colloidal mucilage which primarily consists of xylose, arabinose and galacturonic acid. Galactose and rhamnose are also present. The husk seed contains semi-drying oil, glycoside Audubon, tannin and inactive principle resembling ace tylcholine. Seed husk is used in anti inflammatory, gastrointestinal and genitor-urinary disorders, and is astringent mildly demulcent, diuretic, emollient and laxative. It is also used in chronic cases such as constipation of varied etiology, diarrhea specially of hill origin and of children, dysenteries of amoebic and bacillary origin in piles, decoction in cough and cold. Occurrence and Distribution Plantago ovata forsk require cool and dry weather and sandy soils. It is cultivated in plains of North Gujarat, Punjab plains and the Utter Pradesh. It is also cultivated in Sind, Baluchistan-West wards to Spain and the Canary Island. Chemical constituents Planteose, raffinose, stachyose, sucrose (all in stem, root), fructose, glucose, mucilage containing arabinose, galactose, galacturonic acid, rhamnose and xylose, aucubin etc.

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Plant morphology and flower biology (Fig. 23.1, 23.2, 23.3) Fig. 23.1

ISABGOL PLANTS Plantago ovata is an annual herb, a small stemless plant covered with dense or soft hairy growth. Plant attains a height of 30-45cm. Leaves are filiform or narrowly linear, 10-20cm long, entire or distantly toothed, attenuated at the base, usually 3-nerved. It has a large number of flowering, shoots arising from the main stem. Inflorescence (Fig. 23.2, 23.3) Inflorescence of P. ovata is a spike made up of many florets. The flowers are sessile, small, bisexual and crowded on the main axis scapes longer or shorter than the leaves, glabrous or pubescent. Spike is cylindrical, ovate to oblong in shape. It is 1-4 cm long and is borne at the tip of long wooly peduncle that arises from the axils of the leaf. Subtending each flower is a large broadly ovate or sub orbicular membranous except the narrow midrib bract with a green colored keel. It is 4 mm long, concave, glabrous.

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Calyx (Fig. 23.2) Calyx is about 3 mm long, usually glabrous. The flower possesses four free oblong ovate sepals which is elliptic, obtuse, concave, scarious except midrib which is as broad in the inner as in the outer sepals.

Fig. 23.2

ISABGOL INFLORESCENCE Corolla Corolla is gamopetalous with a papery tube and spreading limb of four rounded ovate, macronate segments. Androecium There are four exerted stamens with long filaments and largely versatile anther which dehisce by longitudinal slits.

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ISABGOL FLOWER

Fig. 23.3

Gynoecium Ovary is superior having two cells with single rule in each cell. Style is slender, pabillate, exserted with simple stigma. Flowers open in basipetal succession. Being protogynous the gynoeciums of the bottom most flower mature first,

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protruding its stigma through the tip of the unopened flower and thus favouring out crossing. The androecium matures latter.

ISABGOL SEED

Fig. 23.4

The fruit The fruit is an ellipsoid capsule obtuse, the upper half coming off as a blunt conical lid, membranous, glabrous, about 8mm long containing 2-3 mm long, boat-shaped, smooth rosy-white, ovoid-oblong seeds. The concave side of the seed is covered with a thin white membrane, produced by fusion of outer layer of ovule together with the inner epidermis, forming the seed coat. The seed epidermis is made of polyhedral cells whose wall is thickened by a secondary deposit, which is the source of mucilage. The coating of the seed provides the husk on mechanical milling. Summary: P. ovata requires cool and dry weather and sandy soils. The seeds are sown during November-December. The crop comes in flowering at about 60 days after sowing and the flowering in completed in next 8-17 days in a spike. Flowers and fruits are born during January-April. The stigma is single with a pointed open in the bud; on opening of flower, it splits into two and become receptive as it protrudes

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out of the bud, reaching up to its open. Anthers in the flower come to dehiscence in about 48 hours after the emergence of stigma. The occurrence of short styled flowers have also been reported in P. ovata and their stigma appears to be single in bud stage having pointed apex covered with hairs. But next day when flower open, it splits into two in the long styled flowers, the stigma becomes receptive in 48 hrs before anther dehiscence. But in short style of flower stigma receptivity synchronizes with the time of anther dehiscence. Thus the long styled flowers were protogynous.

It has also been observed that stigma of P. ovata flowers remains receptive for a pretty long period. On an average 38.55% stigma were found receptive between 7.30 to 8.30 a.m. in the early morning and about 47.53% in the evening hours between 17.00 to 17.30 p.m.; it decreases to 2.98 % at noontime. However, the anthesis is largely (84.61 %) confined to early morning hours of 7.30 to 8.30 a.m. and only 13.74 % was found to occur between 9:30 to 10:20 a.m.

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Floral Biology of Jojoba Family: Simmondiaceae Common Name: Jojoba Genus: Simmondisia Species: chinensis Scientific Name: Simmondsia chinensis

Fig. 24.1

Male Plant

Introduction: Jojoba (Fig. 24.1) is an oil Male flowers yielding plant and pronounced as HO-HO-BA. It is native to the triangle of Sonaran desert of Mexico, California and Arizona. It is found growing naturally in sandy soils, stony and gravel lands of these areas. In India it was introduced about two decades ago and its cultivation has been successfully tried in Rajasthan. Jojoba plant is an evergreen long living bush with a life span up to 200 years. It is a slow growing shrub, which attains a height of 3-5 meters. Jojoba oil and its derivatives are used in cosmetics, pharmaceuticals, lubricant, foods, electrical insulators, foam control agents, high pressure lubricants heating oils, plasticizers fire retardants and transformer oils. Jojoba oil is also a source of long chain alcohols with double bond in slightly different configuration from those in other natural fatty acids. It is also used for skin disorder to reduce inflammation as a cream for sunburn and chapped hands. Floral Biology: Jojoba bushes are either male or female (dioecious) (Fig. 24.4). Tendencies towards hermaphroditism are noted in a few male bushes. These produce all grades of perfect flowers from those with an undeveloped pistil to those with a complete ovary that can even yield fertile seed. Typically flowering occurs at

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Female Plant Pedicel Calyx

Female flower

Stigma

Seed formation

Three partitioning of stigma Fig. 24.2

Fruit

Mature Fruit

FEAMLE FLOWERS alternate nodes along the branches, although some plants produce flowers at each node and others produce them at every third node (Fig. 24.5). Male Plant: In the male plant flowers are born in clusters and the number of flower varies from 7 to 36 per cluster (Fig. 24.3). The males produce pollen and flowers

206

Male flowers

Fig. 24.3

Male flowers At bloom

Sepals Anthers

Parts of male flower

Male flowers

Male flower fully open

containing only stamens. The females produce the fruit and seeds and have flowers containing one ovary with three ovules. These are commonly solitary and have no petals or odors to attract insect (Fig. 24.2). Sex determination: (Fig. 24.4, 24.6) The sex of a young jojoba plan cannot be judged until the first flower bud appears. In precocious individuals this may be in the summer of first year whereas in slow plant this may take until the forth year. In one of the studies it has been shown that male plants grow faster than females during early years, whereas, females grow faster in later years. However it still needs confirmation. Mode of Pollination Jojoba is a cross-pollinated crop and mostly depends upon wind for pollination. Although honeybees and a variety of other insect are often seen foraging for pollens on male or on the hermaphroditic flowers they rarely visit female flowers. Anthesis (Fig. 24.6) Flower bud appears on current season’s growth, mainly the summer and the fall. They usually open in the following spring. This flowering is triggered by the stress of cold or drought or both. The fruits are greenish at first and turn brown as they mature. They contain one seed occasionally, two or three.

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Fruiting branch from female plant

Male inflorescence

Stigma is tricarpellary

Ovary

Fig. 24.4

Stigma is tricarpellary or tetracarpellary

REPRODUCTIVE ORGANS OF JOJOBA Pollen Viability: Pollen viability is very high, however, it varies from genotype to genotype. Pollen stored at room temperature were successfully used up to 45 days for pollinating stigmas of female flowers. However, stigma receptivity is for few hours only. Longer pollen viability is of great use in jojoba. Pollen of desired parent can be transported at normal temperature for use in breeding programmes at distant places.

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Typically flowering occurs at alternate nodes along the branches, although some plants produce flowers at each node and others produce them at Fig. 24.5 every third node. Seeds (Fig. 24.6). Jojoba seeds are far larger than coffee seeds, and their size and shape are not uniform. Of more than 350,000 identified plant species, jojoba is the only one that produces significant quantities of liquid wax esters akin to the natural restorative esters produced by human sebaceous glands. The extractable liquid content of our matured jojoba seeds ranges from 50% to 54%, by weight.

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Fig. 24.6

Parts of seed

OJOBA Floral Biology

Male flower PLANT CANOPY

ANTHESIS

Female flower Different stages of grain maturity

Female flower

Female Branch

Male Flower ANTHESIS

Seed

Mature Grain

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Mature Grain

Floral Biology of Guayule Family: Compositae Genus: Parthenium Species: argentatum Chromosome No. 2n=36-100 or more Scientific name: Parthenium argentatum Gray More than 2,000 species of plants can produce rubber, but guayule (Parthenium argentatum) (Fig. 25.1, 25.3) is the only one other than Hevea (tree) which has had commercial success, dating to the first decade of the twentieth century, when guayule rubber producers operated along the U.S.Mexican border. Recently, renewed interest has developed because of the discovery that guayule rubber has a protein content one-fifth that of the Hevea natural rubber plant.

Crop view

Fig. 25.1

Crop view

Guayule latex is unlikely to cause widespread sensitization associated with Hevea latex and is safe for people with latex allergies. This means that guayule users are far less likely to develop latex allergies and, if already allergic, are safe from adverse reactions. In addition, research performed by USDA and private industry is finding uses for the 85 to 90

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inflorescence

leaves

branch

view from top (inflorescence) inflorescence

floret

BRANCH OF GUAYULE BEARING FLOWERS

Fig. 25.2

percent of the guayule shrub that remains after latex extraction. For example, the recent study showed the guayule fibers to contain a type of natural pesticide to termites and, in addition, to be anti-fungal. The Maricopa Agricultural Center, in cooperation with the USDA-ARS, has maintained and evaluated plantings of guayule, the Chihuahuan desert-native shrub, for the past 10 to 15 years. medical and surgical products with nonallergenic properties. Yields average 1,000 pounds of guayule rubber per acre worth 40 cents per pound. In AZ, a pilot plant is designed to handle 750 tons of

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biomass in anticipation of producing natural latex; if successful, then plans to expand production to NM and TX.

flowers (inflorescence)

Flowering in guayule Fig. 25.3 flowers (inflorescence)

Flowering in guayule

Guayule is a member of the sunflower family, compositae, and belongs to the genus Parthenium. There are 16 species of Parthenium: guayule is Parthenium argentatum, so named because of a silvery shine on its gray-green leaves. It is the only Parthenium species known to produce rubber in large quantity. A bushy perennial shrub, (Fig. 25.3) guayule has narrow leaves, covered in a drought-protecting white-wax, that alternate along the stem, and a canopy of small flowers borne on exceptionally long stems. Usually only about 2 feet (60 cm)

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high, it is long-lived and hardy; it may survive 30 or 40 years under desert conditions where annual rainfall may be less than 10 in. (250 mm). Native to a semiarid area in north-central Mexico and southern Texas, guayule occurs in stands scattered throughout 130,000 sq miles (337,000 sq km) of the Chihuahuan Desert and surrounding regions. In the United States, the shrub is found wild in the Trans Pecos area (Stockton Plateau and Big Bend region of southwestern Texas). Mode of Pollination: Guayule flowers (Fig. 25.2) are pollinated by wind and by insects. The tiny seeds are produced at a prolific rate; a plant can yield several thousand seeds after a single rainfall. Vigorously growing plants bloom and set seed continuously throughout summer and fall. If stored carefully the seeds can remain viable for several decades; some 20 year-old seed were planted in Israel with over 90 per cent germination. Flowers and seeds are produced as early as six months after germination. Guayule is usually propagated by nursery-grown seedlings, though grafts and cuttings can be successful. Young seed requires a simple treatment to break dormancy. Guayule has much inherent genetic variability and is amenable to genetic improvement. Individual plants with chromosome numbers of 2n=36 to 100 or more are known. The guayule types of 2n=36 are completely sexual and reproduce in the usual way, involving pollination (double fertilization). The guayule plants of higher chromosome numbers reproduce without requiring double fertilization (these are termed “apomicts”). Many guayule populations reproduce apomictically, that is, the embryo of their seed arises from a nonfertilized nucleus and thus reproduces a plant that is genetically identical to the parent. With sexual types the plant breeder can develop hybrids with useful characteristics. These hybrid plants can then be induced into apomictic forms to replicate the characteristics of hybrid, generation after generation. This facilitates guayule breeding. Crossability: Guayule can be hybridized with other Parthenium species, e.g., P. incanum, P. tomentosum, and P. srtamonium. Hybrids can be sexual or apomitic. The hybrids with P. stramonium and P. tomentosum in particular show considerable promise for improving guayle, for the hybrids are much bigger plants than guayule and some of them contain rubber. Crosses with P. incanum offer opportunities for greater cold tolerance. Crosses with other Parthenium species have also been tried.

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Floral Biology of Ocimum (Tulsi) Family: Lamiaceae Genus: Ocimum Species: basilicum Chromosome No.: Scientific Name: Ocimum basilicum L.

Habitat - Cultivated but occasionally escaped to waste ground.

Inflorescenc Origin - Native to Asia and Africa. There are many different varieties of basil (commonly called Tulsi in India and is worshiped for its qualities, medicinal and religious) in cultivation. All are delicious. This species is often planted in gardens along with tomatoes, Lycopersicon esculentum, and the two are essential in good Italian sauces.

Fig. 26.1: Inflorescence of Ocimum

Stems – Up to 0.75m

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Source: www.missouriplants.com/Whiteopp/Ocimum_basili...

Calyx

Petals

Anthers

Fig. 26.2

Calyx

Petals

Anthers

Fig. 26.3: Completely opened flower

tall, 4-angled, glabrous or sparsely hairy, branching, herbaceous, strongly aromatic. Leaves - Opposite, petiolate, glabrous, entire or with a few coarse teeth, lanceolate, lanceolate-ovate or ovate.

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Inflorescence - Terminal clusters of whorled flowers (vertcilillasters). Source: www.missouriplants.com/Whiteopp/Ocimum_basili...

Mature seeds

Fig. 26.4: Mature seeds in the inflorescence. Flowers - Corolla white, bilabiate, up to 1cm long. Stamens exerted beyond corolla. Calyx - 5-lobed, upper lobe expanded into a lid or cap over others. Flowering - July - October. Seed – Mature seeds remain dormant for some time, however, it can be sown throughout year in pots as an ornamental plant. But its successful commercial cultivation is possible when sown with the onset of monsoon in July. A few more pictures of Ocimum species have been given below:

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INFLORESCENCE OF OCIMUM Inflorescence is raceme, flowers are present on each node, and are pedicellate. Inflorescence is present in the axil of leaf (see above figure). Flowers may be pink or purple (see figures below). They bear yellow anthers (4) with white filaments. Stigma is bifurcated non-feathery. Each floret has five petals, 4 in gamopetalous condition and one is free. (See figures below). Calyx is spiny. Four sepals have spine at its tip and one (5th) is spineless.

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P A R T O F I N F L O R E S C E N C E O F O C I M U M

219

FLOWER OF OCIMUM

220

ANDROECIUM OF OCIMUM

221

222

CALYX OF OCIMUM 223

Floral Biology of Castor

Family : Euphorbiaceae Scientific name : Ricinus communis Linn. Genus :Ricinus Species.: communis Related species R. chinensis R. zanzibarensis R. cambogensis R. africanus R. mexicanus Chromosome No.: 2n = 20

Fig. 27.1

Castor (Fig. 27.1, 27.2, 27.5) is an annual or perennial oilseed originating in East Africa, especially Tanzania, Kenya, Uganda, it can be found on waste land there in all but the driest places. The plant has a substantial tap root with many lateral branches which can reach a great depth. Annual cultivated varieties reach a height of 0.9 - 1.5m whilst natural perennial varieties can grow as tall as 6m. As a species, the plants are very variable. Leaves are large, glossy and green with pointed lobes and prominent veins, each develops on a long stalk Castor is a semi-tropical perennial crop but grows in warm temperate and tropical regions. Castor requires a temperature of 20° to 26°C with low humidity. It requires rainfall range of 400 to 750 mm. Soils slightly acidic in reaction that is pH 5.0 to 6.5 are preferred, but castor can tolerate upto pH 8.0. Saline soils are unsuitable for castor growth. The caster plant seed and oil have a number of uses as: • Large quantity of castor oil is used in paints and varnish industry. • Used for the production of wetting agents, detergents, sebacic acid, secondary octyl alcohol, heptaldehyde etc.

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• •

Castor oil is traditionally associated with medicinal and veterinary uses for the treatment of obstetrics, dermatology etc. It is the chief raw material for the production of synthetic resins and fibres; as a lubricant, in soap industry; turkey red dying and finning textiles, carbon paper, ointments. An unusual use of castor plant is in Plant Cytogenetics

Inflorescence (Fig. 27.3, 27.4) The inflorescences are borne on the main, lateral and tertiary branches. The inflorescence on the main stem is known as primary candle or spike. The spike consists of unisexual flowers, male flowers known as staminates which are grouped at the base and female flower known as Fig. 27.2 pistillars / pistillate and are located on the upper part of the inflorescence i.e. the plant is monoecious. Stigma is divided into 3 branches towards its upper portion. Each one is further divided into 2-pink fleshy lobes with papillate surface. Ovary is covered usually with fleshy, green spiky outgrowth. The percentage of staminate and pistillar / pistillate flowers varies and can be altered by selection procedure. This species is clearly monoecious (Fig. 27.4) , with separate male and female

225

flowers on the same individual. There are no petals and each female flower consists of a little spiny ovary (which develops into the fruit or seed capsule), and a bright red structure with feathery branches (stigma lobes) that receives pollen from male flowers. Each male flower consists of a cluster of many stamens which literally smoke as they shed pollen in a gust of wind.

Fig. 27.3

Anthesis and Mode of Pollination Castor is a cross pollinating plant but unlike other cross pollinating plant, it is inclined towards some amount of self-pollination. The female flowers open before the male flowers and hence there is a 226

Both male and female flowers are present on the same inflorescence Fig. 27.4

227

Fig. 27.5

228

Fig. 27.6

large degree of cross-pollination. The flowering period may be long. The fruits are spherical capsules which become hard and brittle. The seed capsule has thick walls, is spiny and contains 3 coci (Fig. 27.6, 27.7). Each cocus contains one seed. The period of opening of male flower is longer than that of female flower. The flowering period of one flower lasts for one to two days. The flight of pollen is observed from 7-8 a.m. to 6-7 p.m. in the evening, but the most intensive flight occurs from 9 a.m. to 1-2 p.m. Anthers open quickly at this time forming a pollen cloud.

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Castor bean fruit (Ricinus communis): The spiny, globose seed capsule (left) dries and splits into 3 sections called carpels (center). Each carpel (right) splits open and forcibly ejects a large seed. Source: wanesword.palmar.edu/plmar9.htm

Fig. 27.7 The pollen of castor retains its viability for a long time. The viability of fresh collected pollen is around 80 %; within two days of storage under room condition it is lowered to 75 %; within five days it is 50 % and after 20 days it becomes 25%. Artificial pollination: Emasculation is not required because the species is monoecious. Before application of pollen, the raceme on which the female flower is located should be carefully checked and any interspersed staminate on hermaphroditic flowers removed. When stigma are well exposed, the pistillate flowers can easily be pollinated by dusting pollen on the stigmatic branches. One staminate flower can be used to pollinate several pistillate flowers. The raceme is covered with a bag immediately after pollen is applied. Unless exceptionally hot or wet weather follows pollination seed set should be nearly 100%.

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Floral Biology of Sesamum (Til) Family Genus Species

: : :

Pedaliaceae Sesamum indicum

In addition to the cultivated species S. indicum, two wild species, S. prostratum and S. laciniatum of sesamum (til) (Fig. 28.1, 28.2) are found in India.

Fig. 28.1

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Chromosome Number: The somatic chromosome number of S. indicum is 2n = 26, n = 13. There are 3 broad groups. Sr. No.. 1 2 3

Scientific name S. indicum, S. alabum S. prostratum, S. lacimatum S. radiatum, S. accidentale

Chromosome Number 2n = 26 2n = 32 2n = 64

Group Group I Group II Group III

The generic name Sesamum was derived by Hippocrates from the Arabic ‘Sensin’. Sesame also called ‘Til” or “Gingelli” is one of the oldest of the cultivated oil seed crops. India occupies the first place both in regard to acreage and production. It figures out to be 40% of world production with China at 2nd place. Nearly 60% of world’s acreage is in India, Burma and Pakistan. In India, crop is grown chiefly in the central states both as rabi and kharif crops. China, Sudan, and Mexico are the other important sesamum growing countries. India contributes about 25% of total output. In India, cultivation is mainly confined to Uttar Pradesh, Rajasthan, Madhya Pradesh, Andhra Pradesh, Orissa, Gujarat, Tamil Nadu and Karnataka. Sesame seeds provide an important source of cooking oil as well as being eaten directly as food. The oil is nearly colourless, odourless and remains liquid at low temperature and for this reason may be used as salad oil in cool climate. It may be used to absorb the fragrant essence of sweet scented flowers as a base for perfume. It finds a number of medicinal uses. The oil cake is an edible cake. It is also used as cattle feed especially for milch animals. It can be used as manure. Inflorescence (Fig. 28.2, 28.3) The inflorescence is raceme and the flowers arise in the axils of the leaves and on the upper portion of the stem and branches. Flowers (Fig. 28.2, 28.3) Flowers develop singly in the leaf axils on the upper portion of the stem and branches as a cluster up to 8 in number but normally 2-3 in number or singly. When borne single, two lateral flowers are observed as rudimentary buds (nectarial glands) at the base of fully developed one. They are invariably pilose and show a fair range of variability in size, colour and marking on the inside of the corolla tube. Flowers are borne on very short pedicel. Two short linear bracts arise at the base of the pedicel

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Fig. 28.2

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Fig. 28.3

SESAMUM FLOWRS just below the nectaries which are shed when flowers mature. 234

Corolla Fig. 28.4

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Fig. 28.5

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Fig. 28.6

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Fig. 28.7

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Calyx (Fig. 28.4) Calyx lobes are short, velvety, narrow, acuminate and united at the base. The 5 lobes are of variable sizes, lower are longer than upper ones. Corolla (Fig. 28.4) The flower is zygomorphic with slightly bilabiate tubular corolla of 5 lobes. The upper lip of the corolla is entire, the lower divided into 3 of which the central is longest. Corolla colour is usually white or pale pink but purple colour is also observed. The inner surface of Corolla tube may have red spots or the linear portion only, may be black spotted or occasionally with purple or yellow blotches. Androecium (Fig. 28.4) Stamens are attached with the tube of Corolla. Of the 5 stamens, 4 are functional and 5th either sterile or completely lacking. The 4 greenish white functional stamens are arranged in pairs, one pair being shorter than the other. Anther cells are two, opening longitudinally, connective usually gland tipped. Gynoecium (Fig. 28.4, 28.6, 28.7) Ovary is superior, usually two celled. Cells often completely or partially divided by false septa. The style is terminal, filiform and simple. Stigma is usually two lobed and hairy. Anthesis and Mode of pollination The flowers open early in the morning, wilt in the mid day and usually shed in the evening. Self-pollination is the rule but considerable natural cross pollination takes place by the insects.

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GLOSSARY

ACROPETAL SUCCESSION Flowering starts from the base and proceeds towards the apex in a longitudinal plane. e.g. racemose type of inflorescence (Brassica, Sarson).

ANTHESIS The act of flowering and the period of opening of a flower. APETALOUS FLOWER It is the condition of flower without petals e.g. wheat, rice, bajra etc.

ACTINOMORPHIC/REGULAR Flowers with radial symmetry, which can be divided in many median planes into similar halves, e.g. Brassica / Sarson.

AXILLARY It means in the axil. AUTOGAMY It is the condition of self-fertilization e.g. gram, wheat, rice etc.

ALLOGAMY Cross-pollination e.g. maize, bajra etc.

AWN A stiff bristle like appendage. Collectively known as bread.

ANDROECIUM The whorl of stamens, collective name of male reproductive part of the flower.

AXIAL Belonging to the axis.

ANTHER Enlarged upper portion of the stamen, which contains pollen grains.

BASIPETAL SUCCESSION Flowering starts from the apex and proceeds towards the base e.g. cymose type of inflorescence (rice).

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BISEXUAL/HERMAPHRODITE/P ERFECT Presence of both sexes i.e. androecium and gynoecium in a flower.

COROLLA Whorl of petals (inner to sepals) CROSS-POLLINATION Transfer of pollen from the anthers of flower of one plant to the stigma of flower of another plant of same species.

BASIC NUMBER (x) Haploid number of chromosomes in the ancestral diploid.

CLAW Long narrow base of sepals or petals. e.g. in Brassica spp.

BRACT Leaf in the axil of which a flower arises.

CRUCIFORM Corolla polypetalous, 4 petals, each differentiated into a claw and a limb, and these are arranged in the form of a cross e.g. Brassica.

BRACTEOLE A bract on the floral axis. CALYX The outer whorl of sepals.

CULTIVAR Cultivated variety.

CHASMOGAMY Dehiscence of anthers before the opening of flower, e.g. in wheat and some time in rice.

CYME/CYMOSE Type of inflorescence in which the growth of the main axis or lateral axis is soon checked by the development of a flower at the apex, e.g. wheat, barley.

CLEISTOGAMY Condition of flowers in which they never open ensuring self fertilization e.g. rice, sometimes in gram, wheat, groundnut etc.

DEHISCENCE The bursting open of an anther for the discharge of pollen.

COMPLETE FLOWER Flower containing all the four whorls of sepals, petals stamens and carpals e.g. cotton, sarson, gram.

DETASSEL Removal of tassel (e.g. Maize). DIADELPHOUS Stamens are in tow groups of 9+1 i.e. filaments of nine stamens are fused to form one group and one

CONNECTIVE The mid- rib connecting two anther lobes with the filament.

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stamen remains free, e.g. Gram, pea.

EPIPETALOUS Borne on or arising from the petals or corolla.

DIOECIOUS When the male and the female flowers are born by two separate plants, e.g. date palm, banana, papaya, spinach etc.

EXSERTED Projection outwards as anther project beyond the petals, glumes.

DIPLOID (2n) Organism or cell comprised of two sets of homologous chromosome complements in the somatic cells i.e. having 2x number of chromosomes.

FERTILITY Ability to produce viable sex cells.

DICHOGAMY The ripening of male and female parts of a flower at different times.

FILAMENT Stalk of the stamen.

FERTILIZATION Union of morphologically dissimilar male and female sex cells.

FLORET A small flower from an inflorescence.

EBRACTEATE Without bracts. EAR A large, dense and heavy spike, as that of maize.

FLOWER Cluster of organs directly or indirectly involved in the reproduction through the formation of seed.

EGG The female gamete or germ cell.

FRUIT A matured ovary or a group of matured ovaries.

EMASCULATION Removal of stamens before the bursting of anthers.

GAMETE Sex cell/a mature male or female reproductive cell. Gametes are haploid.

EPIGYNY The condition in which sepals, petals and stamens are present above the ovary i.e. ovary is inferior.

GAMOSEPALOUS Sepals are united at least at the base e.g. gram.

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maize, cucumber, date palm, and papaya.

GLUME Green small bract enveloping flowers of gramineae family. Two empty bracts at the base of each spikelet, e.g. wheat.

INCOMPLETE FLOWER Which lacks one or more of the floral whorls e.g. wheat, rice, maize.

GLABROUS Non-hairy or smooth.

INFLORESCENCE A flowering shoot or flowers born in cluster, e.g. sunflower, onion.

GYNOECIUM Collective name for the carpals.

KEEL Anterior petals in papilionaceae family.

HAPLOID Gametic number. HERKOGAMY Mechanical obstruction to pollination.

LANCEOLATE Wide above the base and tapering to the apex, e.g. in gram sepals are lanceolate.

HYPOGYNY When the ovary occupies highest position on the thalamus, the stamens, petals, and sepals are successively inserted downward (ovary superior) e.g. wheat, gram.

LEMMA The lowermost bract enclosing a floret in grass family. It may bear awn or awn less.

HETEROSTYLY The presence of styles of varying length in different plants of the same species.

LODICULE Scale-like structure at the base of the ovary, two in each floret of a grass spikelet. These swell at the time of anthesis and help in flower opening.

HOMOGAMY When both male and female reproductive organs mature at the same time.

MALE-STERILITY Pollen is non-functional or absent. MONADELPHOUS A single bundle of united filaments.

IMPERFECT FLOWER (UNISEXUAL) Which bears either of the stamens and carpals but not both e.g.

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ones, the two keels are the smallest and innermost).

MONOECIOUS A plant bearing both male and female flowers e.g. maize, caster, cucumber.

PARIANTH A collective term for calyx and corolla.

NODE A point on the main stem from where the leaf arises.

PEDUNCLE Stalk of a flower duster or inflorescence.

OUTCROSSING Cross-pollination or vicinism.

PETIOLE Stalk of a leaf.

OPEN POLLINATION Pollination without control.

PEDICAL Stalk of a flower in an inflorescence.

OVARY The expanded basal portion of pistil having the ovules. Ovules are attached to the ovary with a structure known as placentae.

PEDICILATE Flower possessing a stalk.

OVULE Egg or female gamete present in ovary, which becomes seed after fertilization.

PERFECT Hermaphrodite or bisexual flower/both androecium’s and gynoecium present in a flower.

PALEA Presents opposite to lemma in a floret present in the spikelet of spike, membranous, scale like awn less structure, covering from one side the reproductive organs of flower (floret).

PISTIL/CARPEL The seed-bearing organ in the flower composed of the ovary, the style, and the stigma. PISTILLATE When stamens are absent in a flower.

PANICLE A compound inflorescence with pedicilate flowers.

POLLEN GRAIN Male gametophyte which originates from a microspore. Minute powder like grains contained in the anther.

PAPILIONACEOUS FLOWER 5 petals (one standard is exterior and largest, two wings are lateral

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POLLINATION Transfer of pollen grains from the anther to the stigma.

POLYPETALOUS It means that petals are free e.g. gram, cotton, sarson.

POLYADELPHOUS Stamens united by filaments into numerous bundles.

POLYSEPALOUS When sepals are, free from each other e.g. sarson.

POLYANDRY Infinite number of stamens in a flower.

RACEMOSE/RACEME Inflorescence of indefinite type in which the oldest flowers are lower most e.g. sarson.

POLYGEMOUS Bearing unisexual and bisexual flowers on the same plant.

RACHIS The main axis of an inflorescence or the axis of a pinnately compound leaf to which leaflets are attached.

PROTANDRY Anthers maturing earlier than stigmas become receptive e.g. cotton, marigold.

SELF-POLLINATION Transfer of pollen from an anther to the stigma of same flower.

PROTOGYNY Gynoecium matures prior to anther dehiscence, e.g. bajra.

SESSILE Devoid of stalk i.e. stalk is absent e.g. wheat spieled.

PUBESCENT Hairy.

SPIKE Inflorescence in which sessile flowers are arranged along a longitudinal axis, with oldest flowers at the base and youngest near the apex. E.g. wheat, barley.

PERIGYNY (Ovary half inferior) when the thalamus forms a cup like it and carrying sepals, petals and stamens/Receptacle in concave shaped at the bottom of which ovary is present. To the edge structure enclosing the ovary but remaining free from s of the receptacle, sepals, petals and stamens are attached.

SPIKELET A unit of inflorescence in grasses composed of culms, rachilla and the florets.

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which in turn covers the two interior ones (keels), e.g. gram, pea, arhar.

STAMEN A male organ of flower, consisting of filament, connective and an anther.

VALVATE TYPE AESTIVATION when the sepals or petals do not overlap but lie close to each other by their margins.

STAMINATE When carpals are absent in a flower.

X Basic number of chromosomes.

STYLE Stalk connecting ovary and stigma.

ZYGOMOROHIC/IRREGULAR Flower, which is divisible into two equal halves in one particular plane only, e.g. wheat barley, gram.

SYNCARPOUS When carpals are fused together in an ovary e.g. sarson. TETRADYNAMOUS It means four stamens are long while two are short e.g. sarson

Flower structures Source: www.pollinater.com/hnd_pollination.doc

TILLER A sprout or stalk from the roots or base of the main stem or the lower nodes.

Male: filament: The stalk or organ that holds the anthers, absent in some flowers. anther: The pollen producing organ of flowers. Some produce pollen on the exterior, some produce it internally and release it thru pores. stamen: The entire male structure, including filament and anther. pollen: The male reproductive spores of a flower. pollen grain: A single male reproductive spore. pollen tube: A growth of germinating pollen down the style of the pistil, to the ovary where it

TWISTED TYPE AESTIVATION When the sepal or petal overlaps the neighboring sepal or petal on one side and is overlapped by another sepal or petal on the other side resulting in one-sided twist, e.g. cotton. VIABLE able to live and grow. VEXILLARY TYPE AESTIVATION when the posterior petal (standard covers the two lateral ones (wings),

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same plant, as with cucumbers and melons. dioecious: Having separate male and female flowers on separate male and female plants, as with kiwi fruit or holly.

joins with an ovule in fertilization. Female: stigma: The sticky end of the pistil, where pollen adheres in pollination. Often it is divided into lobes. style: The stalk that supports the stigma. pistil: The style and stigma together, the external female structures of the flower ovary: The organ which contains the ovules or incipient seeds. If only one ovule is present it is also called the carpel. If there are many ovules, the ovary may be divided into segments; each segment is then called a carpel. Generally the ovary becomes the fruit, while the ovules become the seeds. ovule: The female reproductive cell is enclosed in the ovule, which, when fertilized, becomes the seed. carpel: see ovary petal: A flower appendage, usually showy to attract attention from pollinators. sepal: A protective flower appendage, the remnants of the bud enclosure, usually green and inconspicuous.

Pollination Terms pollination: The transfer of pollen from anther to stigma, in plant reproduction. pollinator: The agent that transfers pollen in pollination. Pollinators are most often bees, but can be birds, butterflies, beetles, bats or even humans. pollenizer (sometimes pollinizer): A plant that provides viable pollen for pollination. Some plants mutually pollenize each other, as two varieties of apple or cherry. Some pollenizers are male plants that provide no fruit, as in kiwi fruit, or plants that have little commercial value but are used simply to provide pollen, as crab apples in an apple orchard. A common error is to call plants pollinators, or to say one plant pollinate another. Plants cannot pollinate; they pollenize.

FlowerTypes perfect flowers: Having both male and female organs within the same flower. Some people erroneiously think that this means the flower will self pollinate. monecious: Having separate male and female flowers, but on the

sterile pollen: Pollen which is incapable of germination. These plants cannot be used as pollenizers. fertilization: The joining of male and female gametes in the ovary, in plant reproduction.

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self incompatible or self sterile or self unfruitful: A plant whose stigma will place chemical or physical barriers against its own pollen. self fertile: Pollen from the same plant or a clonal fruit variety can germnate and fertilize the ovules.

self pollenisation: A plant that does not truly self pollinate; it requires a pollinator, but can achieve a commercial crop with only its own pollen. Remember that an orchard block of a single variety is genetically a single plant (clone)

Self fertile and self sterile and not absolutes in most cases but rather relative. Many plants that are regarded as self fertile will yield better in quantity or quality when cross pollinated.

cross pollination: Transfer of pollen between two genetically different plants. Self sterile plants require cross pollination. parthenocarpic: The ability to produce (seedless) fruit without pollination. Some citrus is parthenocarpic, also there are some cucumber parthenocarpic varieties. Not all seedless fruit is parthenocarpic. Seedless watermelons require pollination but the seed usually does not mature.

self pollination: The plant with no aid from any pollinator can form seeds. Peanuts, green peas, and green beans are examples where the flower actually grows the anthers and stigma into direct contact. It is misleading to use the term for plants that require a pollinator to move pollen, such as peaches, or for plants that only sometimes self pollinate, but require aid to make a commercial crop.

cultivar: A cultivated variety.

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General features of flowers of in- and out-breeders and old and new family names

Flowers have certain visible characters that can easily categorize them as outbreeders or inbreeders OUTBREEDER INBREEDER self-incompatible self-compatible many flowers few flowers large flowers small flowers bright colors mono-colored nectaries present nectaries absent scented flowers unscented flowers nectar guides nectar guides present absent anthers far from anthers close to stigma stigma many pollen grains fewer pollen grains style exserted from style included in flower flower stigmatic area well-defined

stigmatic area poorly-defined

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The old names of some families have been changed. The new names are given below: Old Name New Name Cruciferae Brassicaceae Papilionoldeae Fabaceae Umbellifcrae Apiaceae Compositae Asteraceae Labiatae Lamiaceae Graminae Poaceae Palmae Arecaceae Caesalpiniaceae Cassiaceae Mimosoidae Mimosaceae The old family Leguminosae now includes three sub-families – (i) Mimosoideae, (ii) Caesalpinioideae and (iii) Papilionoideae. These subfamilies have now been raised to the level of families and are called – (i) Mimosaceae, (ii) Caesalpiniaceae

Crops and Their Time of Anthesis Note: Tme may vary according to season, location and other environmental conditions, however, following are the general observations: Name of Crop Rice Wheat Maize Sorghum Pearl millet Bengal gram of chick pea Green Gram Black gram Cowpea Peas Soyabean or Glycine Sugarcane Groundnut Sunflower Arhar (Pigeon pea) Linseed Cotton

Botanical name Oryza sativa Triticum Zea mays L. Sorghum Spp. Pennisetum typhoides Cicer arietinum Phaseolus aureus Roxb Phaselus mungo Linn Vigna sinesis L. savi Pisum sativum Linn Glycine max L. Saccharum spp. Arachis hypogaea Linn Helianthus annus Linn Cajanus cajan Linum ustitatissimum Gossypium sp.

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Time of Anthesis 10 a.m. – 12 noon 9 a.m. – 2 p.m. 12 midnight – 2 a.m. 8 a.m. – 2 a.m. 2.30 a.m. – 3 a.m. 9 a.m. – 10 a.m. 9 p.m. – 3.00 a.m. 6 a.m. – 8 a.m. 4 p.m. onward 7 a.m. – 9 a.m. -- -3 a.m. – 8 a.m. 5 a.m. – 6 a.m. 3 p.m. – 4 p.m. 9.30 a.m. 10 a.m. – 12 noon

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Blackhurst. H. T. and Miller, J. C. Jr. 1980. Cowpea. In: Hybridization of Crop Plants, Walter R. F. and Hadley, H. H. (eds.) American Society of Agronomy and Crop Science Society of America, Madison, Wisconsin, USA. pp. 327-337. Briggs, F. N. and Knoles, P. F. (1967) Introduction to Plant Breeding, New York. Brown, J. G. W. and Lee, J. A. 1976. Effect of emasculation on boll set in three stocks of cultivated Gossypium. Crop Sci. 16: 599-601. Burton, G. S. 1966. Pearl millet breeding. African Soils 11: 39-47. Byth, D. E., Green, J. M. and Hawtin, G. C. (1980) ICARDA chickpea breading strategies In: Proc. Int. Workshop on chickpea breeding Improvement. ICRISAT, India. Feb.-2 March 1979, 11-27. Capinpin, J. M. and Guevara, C. F. 1951. The floral biology and fructification of peanut, Arachis hypogaea. Philipp. Agric. 35: 137-192. Chatterjee, D (1948) A modified key and enumeration of species of O. sativa L. Ind. J. Agric. Sci. 18: 185-192. Chaudhary, B. S., Paroda, R. S. and Solanki, K. R. 1974. A new crossing technique in clusterbean (Cyamopsis tetragonoloba (L.) Taub.). Curr. Sci. 43: 456-459. Chaudhary, J. B., Mehta, R. K. and Joshi, A. B. 1965. Pollination in berseem. Indian J. Genet. 26: 118-120. Chhidda Singh (Modern Techniques of Raising Field Crops. Professor of Agronomy (Ext.) G.B. Pant University of Ag. & Tech. Pantnagar, U.P. Oxford & IBH Publishing Co. Pvt. Ltd. Chiang, M. S. (1974) Cabbage, pollen germination and longevity. Euphytica 23: 579-584. Chilton, S. J. P. and Paliatseas, E. D. 1956. Studies on the flowering of sugarcane. Int. Soc. Sugarcane Technol. Proc. 9: 652-656. Chopra, V.L. (2001). Breeding Field Crops, Oxford and IBH Pub. Ltd. , New Delhi. Pp 580. CIMMYT. 1976. The CIMMYT Wheat Training Manual. Mexico 6, P. F. Coffman, F A. 1922. Pollination in alfalfa. Bot. Gaz. 74: 197-203. Crook, W. J., Casady, A. J. and Camphile, L. C. 1972. Scissors emasculation of sorghum. Crop Sci. 12: 709-710. Culbertson, J. O. (1954) Breeding Flax. 1954. Adv. Agron. 6: 174-178. Dangi, O. P., Paroda, R. S., Kishor, S. and Solanki, K. R. 1976. Crossing technique for enhanced seed setting in oats (Avena sativa L.) Forage Res. 2: 73-76. Das, P.C. Oilseed crops of India. 1997 Senior Teachers in Agriculture Barabainan Union Samabay Krishi Samity Sikshaneketan Burdwan, West Bengal. Kalyani Publishers.

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