For production of seeds for cultivation or developing new varieties or hybrids, certain standards should be followed to get good quality and pure seeds.
1. PRINCIPLES OF SEED
TECHNOLOGY 3(1+2)
SEED PRODUCTION IN COTTON VARIETIES
AND HYBRIDS
BY TO
BASKAR S Dr.DHIVYAPRIYA D
BATCH-A Asst. Prof.
CB.AG.U4AGR19018 19GPBB212
2. COTTON (QUEEN OF FIBRES)
BOTANICAL DESCRIPTION
Scientific name : Gossypium sp.
Family : Malvaceae
Leaves : Three lobed leaves
Branches : Sympodial & monopodial
3. Floral biology :
Bisexual flowers on sympodial branches
Simple, solitary, terminal, hermaphrodite
5 sepals, united and cup shaped 5 petals
Yellow to cream in colour with purple spots
After pollination, light pink to purple in colour (within a day)
Monodelphous, often cross pollinated (>60%)
4. Anthesis :
Anthesis time will be vary on different species.
Climatic factors (temperature) also affect it.
Asiatic cotton – 8 to 10 am
American cotton – opens earlier
Receptivity of stigma – 8 to 10 am
MAJOR 4 CULTIVATING COTTON SPECIES
Gossypium arboreum (K 10) (2n=26)
Gossypium herbaceum (Uppam) (2n=26)
Gossypium hirsutum (MCU varieties) (2n=52)
Gossypium barbadense (Suvin & Suguna) (2n=52)
5. METHOD OF SEED PRODUCTION
Seed production techniques will be different for both varieties and
hybrids.
1. VARIETIES
Open pollination is done under isolation and varieties are
multiplied. For nucleus seed production, selfing of flowers is done
with cotton lint (dipped in clay or red earth).
2. HYBRIDS
It is of two types. They are interspecific and intraspecific
hybrids.
Interspecific hybrids
Crossing among same genus of different species
Hybrids G. hirsutum x G. barbadense
(Parentage)
i) Varalakshmi : Lakshmi x SB298
ii) Jayalakshmi/ DCH 32 : DS 28 x SB 425
iii) TCHB 213 : TCH 1218 x TCB 209
6. Intraspecific hybrids
Crossing among the same species of different subspecies
Savitha : T 7 x M 12
METHODS OF HYBRID SEED PRODUCTION
1. Conventional method
Emasculation and dusting is the conventional method for
hybrid seed production.
Select the female line flowers at 1 day before opening (3-6 pm)
Remove the staminal column by needle
Cover the female parent for identification
Select the male parent at the time of anthesis
Pluck the male parent & dust the female parent
Cover the female parent to prevent the contomination by foreign
pollen
One male parent is enough to dust 4-5 female parents &
receptivity of stigma is 46 hrs.
7.
8. STEPS IN HYBRIDIZING TECHNIQUE
Emasculate and dust the flowers (buds) appearing during first six
weeks of reproduction phase.
Emasculation time – 3 to 6 pm & pollination time – 9 to 12 am
Emasculated and pollinated female parents are covered with paper
bags and choose optimum aged and sized parents.
Stop the crossing programme after 9th week and remove the further
appearing buds.
Nip the top and side shoots to stop further vertical and horizontal
growth.
Optimum irrigation should be given
Pick the ripened and opened bolls and sort it out to check that they
are crossed bolls and stored in gunny bags.
Rain touch or hard lock cottons are separated to avoid the poor
germination.
Store the seeds in cool dry place till it is given to processing unit.
9. 2. Non conventional method
Genetic male sterility (GMS) is the non conventional
method for producing hybrids.
In this, female parent is segregated into 50:50 ratio of male
sterile and male fertile plants.
Then, male fertile are removed and male sterile plants are
crossed with requiring male line.
e.g. Suguna : Gregg x K 3400
10. FIELD REQUIREMENTS OF COTTON FOR BETTER
GROWTH
1. Land
Fertile black cotton soil with ridges & furrows which should be free
volunteer plants, pest and pathogen (wilt disease)
2. Season
Winter crop : August – September
Summer crop : February – March
3. Seeds & sowing
Tagged seeds should be obtained from authenticated sources (agri
clinic) & seeds are dibbled at optimum depth (4-8 cm).
4. Seed treatment
Delinting ( 100ml of concentrated sulphuric acid in 10 litre of water
for 1 kg of seeds at 2-3 min and washed by water) to remove cotton
fuzz around the seeds.
Seed hardening 1% prosopis & pungam leaf extract to resist water
stress problems.
11. Azospirillum is mixed with cotton seeds at 600 g/ha.
Then 2kg of azospirillum /ha is mixed with 25kg of FYM and
25kg of soil and applied on the seed line.
5. SEED RATE (kg/ha)
Varieties : 15 kg (fuzzy seeds), 7.5kg (delinted seeds)
Hybrids : 3.5 kg (Jayalakshmi), 1 kg (TCHB 213)
Male : 2kg
Female : 4kg
6. Spacing
For hybrids, planting ratio is 8:2 of female and male parents.
Duration Varieties Hybrids
Long duration 90 x 30 cm 120 x 60 cm (female)
Short duration 60 x 30 cm 90 x 60 cm (male)
12. 7. Isolation distance (m)
8. Manure & fertilizers
Compost – 12.5 tons/ha
Total NPK – 100:50:25 kg/ha
Basal NPK - 50:50:25 kg/ha
Top dressing – 25 kg/ha @ 40-45 days after sowing
25 kg/ha @ 70-75 days after sowing
9. Foliar spray
2% of DAP on 60th,70th,80th & 90th day after sowing
10. Micronutrient application
Mix 12.5 kg of TNAU micronutrient mixture with 37.5 kg of
sand (to make it as 50kg) for 1 ha.
Type Foundation seed Certified seed
Varieties 50m 30m
Hybrids 50m 30m
13. 11. NAA application
40 ppm of NAA (40 mg of NAA in 1 litre of water) at 40/45th
day. Repeat it after 15 days of first spray.
12. Irrigation management
Once in 10 days. Regular irrigation in critical stages (from
boll initiation to boll maturation stages.
14. 13. Intercultural operations
Topping
Nip the top and side shoots
(10 – 12th) to stop excessive
vegetative vertical and horizontal
growth.
Roughing
To maintain purity, roughing
is done for off types, selfed plants
from vegetative to harvest phase.
It depends on the plant
characteristics such as leaf and boll
size, flower colour, number of
sympodia, hairiness etc…
15. 14. Specific problems
Boll shedding will occur in hotter
climate or in lesser irrigation.
For controlling, 40ppm of NAA &
20ppm of cycocel (ccc) is sprayed.
15. Field standards
For foundation seeds, maximum
permitted off type is 0.1% (both
varieties & hybrids).
For certified seeds, maximum
permitted off type is 0.2% (varieties)
& 0.5% (hybrids).
16. 16. Harvesting stage
Initiation of hair line cracks on dried bolls
Hand picking is done at 45 days after anthesis (10 – 11 am)
Moisture content – 30 to 35 %
Normally, 7 pickings are done but for seed production early 4-5
pickings are done.
Kapas are taken from well burst bolls only.
17. PROCESSING
Kapas sorting – Hard locks (without proper bursting) & pest
attacked (boll worms) are sorted manually for good germination.
Ginning – It is done to remove dust, dirt and fuzz from seeds in
processing unit.
Acid delinting – Using sulphuric acid chemically lint is removed
from the seed.
18. Grading – Seeds are graded by specific gravity method by
flotation technique using water in which sinkers (brownish) are
good seeds. In this, floating, reddish (immature) & insect damaged
(holed) seeds are removed. Then, seeds are dried.
Certification – Seeds are certified by seed inspector or
certification officer based on its physical and genetic purity and it
is sealed in bags. It is used for commercial sale and uncertified
seeds are used by that company for further multiplication.
20. SEED STORAGE
Graded good quality seeds are stored in moisture pervious
container (upto 8-9 months) or in moisture proof container (upto
12-15months).
It is treated with thiram @ 2.5g/kg of seeds which preserves
storability.
In mid storage, seeds are shaded and sun dried to maintain 10-
12 % of moisture content.
