QUALITY SEED PRODUCTION IN COTTON HYBRIDS

Land Requirement

• Land should be free of volunteer plants.
• The previous crop should not be other varieties or hybrids of the same crop. It can be the same hybrid parental lines, if it is certified as per the procedures of certification agency.

Field Standards

A. General Requirements

Isolation

• Cotton seed production fields shall be isolated from the contaminants by allowing the isolation distance as specified below.

B. Specific requirements

Seed rate

• Female parent : 4 kg/ha
  Male parent : 2 kg/ha
  Female and male block ratio : 8:2

Spacing

• Male parent : 60x45 / 90x60 cm
  Female parent : 120x60 cm

Fertilizer requirement

• Apply NPK @ 16:16:16 kg/ac as basal.
• Top dress N @ 8kg/ha on 60 and 90 days after sowing.

Earthing up

• Reform the ridges and furrows after first top dressing in such a way that the plants are in the center of ridges and well supported by soil.

Foliar application of nutrients

• Foliar spray of 100 ppm boric acid or 0.5% zinc sulphate for male parent during flower initiation to improve the pollen viability and pollen production.
• Foliar spray of salicylic acid @ 250 ppm at 90 days after sowing to increase the seed set.
• Foliar spray of 2% DAP for 4 times at 10 days interval from flowering to boll development for better development of crossed bolls.

Special operations

Emasculation and Dusting

• Emasculation and dusting should be done in all buds appearing during the first six weeks of reproductive phase. At any case, crossing programme should be closed within the 9th week from the commencement of crossing. The flowers appearing subsequently should be removed. This process will facilitate the better development of crossed bolls.

• For emasculation, select the buds with optimum size which are likely to open in the next day.
• Emasculation should be done daily between 3 to 6 pm.
• Cover the emasculated buds with red colour butter paper cover
• Collect the pollen from the flowers of the male parent on the day of opening
• Dust the pollen on the emasculated female buds between 8 am to 11 am

Topping

• Remove the apical bud manually on 90th and 105th days after sowing to enhance the sympodial branch formation.

Harvesting

• Fully opened kapas obtained from four to six pickings should be used for seed purpose.

Kapas sorting

• Stained, discoloured, hard locks, unopened, pest and disease infested kapas should be removed.

Ginning

• Ginning of cotton should be done only in the approved ginning unit. .

Seed drying

• Ginning of cotton should be done only in the approved ginning unit. .

Seed processing

• During seed processing, the immature, ill-filled, broken seeds of cotton, other crop seeds and inert matter are removed.
• Seeds are graded based on density using specific gravity separator.

Pre-storage Seed treatment

• Treat the seeds with carbendazim @ 2 g / kg of seed.

Seed storage

• Store the seeds in gunny or cloth bags for short term storage (8-9 months) with the seed moisture content of 9-10%.
• Store the seeds in polylined gunny bags for medium term storage (12-15 months) with the seed moisture content of 7-8%.
• Store the seeds in 700 gauge polythene bags for long term storage (more than15 months) with the seed moisture content of less than 6%.