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Ashish sheera cotton
- 1. Floral Biology Of Cotton SUBMITTED TO, Dr P.K Rai Department of Genetics and Plant Breeding SUBMITTED BY ASHISH SHEERA ID:-16MSCGPB043
- 2. SCIENTIFIC CLASSIFICATION Kingdom: Plantae Order: Malvales Family: Malvaceae Subfamily: Malvoideae Tribe: Gossypieae Genus: Gossypium
- 3. There are four commercially grown species of cotton, all domesticated in antiquity: Gossypium hirsutum – upland cotton, native to Central America, Mexico, the Caribbean and southern Florida (90%of world production) Gossypium barbadense – known as extra-long staple cotton, native to tropical South America (8% of world production) Gossypium arboreum– tree cotton, native to India and Pakistan (less than 2%) Gossypium herbaceum– Levant cotton, native to southern Africa and the Arabian Peninsula (less than 2%) The two New World cotton species account for the vast majority of modern cotton production, but the two Old World species were widely used before the 1900s. While cotton fibers occur naturally in colors of white, brown, pink and green, fears of contaminating the genetics of white cotton have led many cotton-growing locations to ban the growing of colored cotton varieties, which remain a specialty product.
- 4. CHARACTERISTICS Habitat Terrestrial Leaf type the leaves are simple (A simple leaf has a single blade) Leaf arrangement alternate: there is one leaf per node along the stem Pollination Often cross pollinated Chromosome no. – 2n=52 Floral Formula: K(5), C5 , A(∝) , G (5)
- 5. Flower symmetry there are two or more ways to evenly divide the flower (the flower is radially symmetrical) Number of sepals, petals or tepals there are five petals, sepals, or tepals in the flower Fusion of sepals and petals the petals or the sepals are fused into a cup or tube Stamen number 13 or more Fruit type (general) the fruit is dry and splits open when ripe Fruit length 30–50 mm
- 6. COTTON FLOWER The petals of the cotton flower are a creamy white to yellow when the flower first opens. They are narrow at the base and broad at the tip. The petals darken, usually to a dark pink at the end of the first day. Below is a cross section through a petal. The flower has three bracts, usually closed about the square. It also has a calyx, which surrounds the developin bud. Both the bracts and the calyx serve to protect the flower. In the center of the flower is a five lobed pistil, surrounded by many stamens. Each of the stamens has a two lobed anther that releases pollen. Each pollen grain is viable for about 12 hours after release.
- 7. The flower has a superior ovary, consisting of two or more locules, or seed chambers. Depending upon the species of cotton, each seed chamber can have 8-12 ovules, 5-9 of which usually mature. A flower bud, or "square" is produced at every node on the fruiting branches of the cotton plant. The first square can be seen 35 to 45 days after the plant begins to grow. The mature flower needs 25 days to fully develop, the buds that are lowest on the plant develop first. The petals of the flower appear to be a light yellow or white when open. After one day, the petals turn dark and the flower closes. The flower is usually self pollinated. Pollination usually occurs within that first day, and the ovules are fertilized about 30 hours after pollination.
- 8. • The developing flower consists of concentric whorls, the outer one being the bracts. Inside the bracts is a whorl of sepals (collectively, called the calyx, which are green and completely enclose the inner developing whorls . The next whorl consists of the petals (collectively, called the corolla). The next whorl is composed of stamens, the structures responsible for producing pollen. The white mass in the center of this bud is most likely immature stamens. The gynoecium (not visible here), or female reproductive structure, develops within the whorl of stamens. • As the square develops, the calyx is pushed open, and petals can be seen. • After 35 to 45 days, the flower opens for a period of one day. The flower either self pollinated, or sometimes (although rarely) is cross pollinated by insects. After the ovules are fertilized, the bolls require 40-70 more days to fully mature. The length of time to maturity depends upon the species of cotton.
- 9. FLORAL CHARACTERS: Pedicellate, complete, cyclic, bracteolate in the form of epicalyx, hermaphrodite, actinomorphic, hypogynous, regular and pentamerous. PEDICELLATE-A flower with a stalk is called pedunculate or pedicellate SEXUALITY: Bisexual- Bisexual or perfect flowers have both male (androecium) and female (gynoecium) reproductive structures, including stamens and an ovary. SYMMETRY: Actinomorphic- . Actinomorphic flowers are also called radially symmetrical or regular flowers. Flowers that are radially symmetrical so that they are able to be bisected into similar halves in more than one vertical plane, forming mirror images. a single flower arising from the axil of the leaf.
- 10. INFLORESCENCE: Cyme Or Solitary- in cyme oldest flower terminates the main axis. Solitary means EPICALYX: a series of small sepal-like bracts forming an outer calyx beneath the true calyx Number- 5-7 Colour – Green An additional whorl below calyx CALYX: Number- 5 Fusion- Gamosepalous- having the sepals united. Aestivation- Valvate Aestivation or estivation refers to the positional arrangement of the parts of a flower within a flower bud before it has opened.
- 11. Valvate aestivation- margins of adjacent petals or sepals touch each other without overlapping. Shape –bell shaped Colour- Green COROLLA: Number- 5 Fusion- Polypetalous-having a corolla composed of distinct, separable petals Aestivation- Twisted ANDROECIUM: 1.Stamen Number.-Indefinite 2.Cohesion- Monoadelphous. i.e forming a staminal tube around the style. united into one bundle or set by their filaments. 3.Adhesion -Epipetalous i.e. filaments adnate to the basal part of the petal. 4. Anthers Reniform, i.e. kidney shaped 5.Free and monothecous (Monothecous means one chambered)
- 12. GYNOECIUM: 1.Carpel Number of carpels-5, (Pentacarpellary) 1.Fusion – Syncarpous- having the carpels united. Ovary- Superior(A superior ovary is an ovary attached to the receptacle above the attachment of other floral parts), pentalocular with 1 or 2 ovules in each locale Style- Long, united below, free above, passes through staminal tube Stigma-Five in number Placentation- Axile ( The ovary is sectioned by radial spokes with placentas in separate locules)
- 13. Floral diagram
- 20. Thank you