Lalit Kumar
2019A74M
lkgather99@hau.ac.in
CCS Haryana Agricultural
University, Hisar
Introduction
• Cotton – King of fibres
• Cotton – white gold, one of the most important
commercial crop of the world
• Cotton constitutes 85% of raw material for
textile industry.
• Around 80% of pesticide is consumed by cotton.
• Seed contain alkaloid gossypol
• Cultivated all over the world, India ranks first in
area and 2nd in production.
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Scientific classification
• Kingdom : Plantae
• Order : Malvales
• Family : Malvaceae
• Subfamily : Malvoideae
• Genus : Gossypium
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Floral Biology
• Cotton flowers occur singly (solitary)
• Produced on sympodial branches from terminal
buds
• Base of flower surrounded by thee leaf like
triangular bracts (epicalyx)
• The calyx is reduced to a small cup shaped
structure with five lobes
• 2 type branching:
vegetative or monopodial
Reproductive or sympodial
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Stages of flowering
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Parts of flower
1. Calyx :
It has 5 persistant, shallow,
cap like sepals with variable
lobes. It is truncate and
undulate that adheres tightly
to the base of the boll as it
develops.
2. Epicalyx :
It consists of three persistant
modified leafy bracts, also
called as bractioles.
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Corolla
• Bright yellow
• 5 petals
• Gamopetalous
Androecium
• Numerous stamens (90-100)
• Filaments are united to form a tubular staminal
column (monoadelphous) around the style
• Anthers arranged in 5 rows on staminal tube
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Gynoecium
• Pistils consists of 3-5 carpels corresponding to
locules in fruits
• Overy – superior
• Slender styles with varying length
• Style - single
• Ovary develops into a capsule or bole
• Each locule have 8-12 ovules
• 5-9 locules matures
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Anthesis
• Twisted corolla emerges from the bracts
• Variation in time of flower opening occurs,
maximum flower opening 8-10 a.m
• Stigma becomes receptive soon after flower
opening
• Stigma receptivity- 7 hrs
• Pollen viability- 12 hrs
Pollination
• Self pollinated crop because pollen is shed
directly on stigma
• Cross pollination due to insects
• Cross pollination ranges from 5-25% sometimes
exceeds 50%
• Hence cotton is an often cross pollinated crop
• Fertilization is completed in 36-40 hrs after
pollination
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Selfing
1. Selfing method :
A mature flower bud is selected and the corolla is tied
with a piece of thread. In order to keep the threads in
position apply a bit of clay over the knot. This will
avoid contamination of stigmatic surface by foregion
pollen.
2. Paper cover method :
A small paper cover is put over the mature flower bud
before anthesis and kept for 2-3 days.
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Crossing
1. Doak’s method :
• A mature flower bud is selected from which the
corolla is removed and total staminal column is peeled
off by making a narrow cut at the lower portion of
flower bud.
• Care should be taken not to injure the overy.
• After the emasculation, cover the flowers with red
paper covers.
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2. Soda straw method :
• The upper part of the corolla is removed from the
mature flower bud by making a circular cut at the top.
Then a small piece of soda straw is inserted over the
stigma, so that the stigmatic region is separated from the
anthers.
• The tip of the straw is bent to close the opening. Next
morning a few mature anthers collected from the male
parent are crushed and dropped into the soda straw and
cross pollination is effected.
• After crossing, cover the flowers with white cover.
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SYMBOL OF TRUST
