Cotton

Varieties and Hybrid Cotton

A brief note on recommended and cultivated varieties/hybrids of cotton in Karnataka.

• Frequent and drastic changes are recorded in cotton varieties/hybrids recommended and cultivated in entire country. Such changes are not an exception in Karnataka.
• From cultivated species, varying growing conditions, widely differing quality parameters and market rates offered have necessiated the cultivation of different varieties of cotton.
• In Karnataka, traditional cotton growing districts like Dharwad, Gadag, Haveri, Belgaum, Bijapur were growing Asiatic cottons prior to 1880. But, introduction of G. hirsutum varieties resulted in replacement of Asiatic varieties with upland cotton in majority of area.
• In the last 25-30 years, cotton growing areas have witnessed two phenomenal changes:
• Replacement of all Asiatic varieties by G. Hirsutum varieties and interspecific hybrids – except a small belt in chitradurga district.
• Reduction in area under cotton cultivation in traditional areas and expansion of cotton cultivation in non-traditional areas like Shimoga, Mysore districts. Parts of South Kanara, North Canara, Chamarajanagar, Davanagere have been reported to have taken up cotton cultivation. Cotton cultivation is drastically reduced from Bijapur, Bellary and Raichur districts.
• The interspecific hybrids – released originally for irrigated areas – are popularly grown in rainfed tracts of traditional and non-traditional areas. They occupy 35-40% of total cotton area in Karnataka.
• Although large number of varieties were recommended and grown earlier – only few are now actually cultivated. Similarly, along with officially recommended and cultivated hybrids, many private hybrids (hybrid cottons released by private companies) have been cultivated on a large area.

Varietal selection

Selection of varieties/hybrids and good quality seeds which suit to the prevailing environmental condition are the key points to be considered in cotton production. The different varieties/hybrids that have been released are given below.

Note: 1. Grow only those varieties/hybrids recommended for the region/zone and use seed only from authenticated agencies.

2. More profit can be gained through growing Bt cotton hybrids/varieties with low inputs.

Male Sterility in Cotton

• Both genetic and cytoplasmic male sterility are reported.
• Although genetic male sterility results in hybrids with higher heterosis genetically male sterile hybrids seggregate in F1.
• Overcoming this problem, first genetically male sterile based hybrid was released in M.P., Gujarat and named as Jagannath.
• Efforts are made to use Gregg male sterile lines to cross suitable parents.
• Recently, monogenic genetic male sterility is also identified in G-arboreum paving the way for future male sterile hybrids in Asiatic Cotton.
• Cytoplasmic male sterility is also noticed in G-hirsutum – which offer no problems of seggregation.
• In future years male sterile based hybrids occupy larger share of commercial hybrids, as the cost of seed production will be drastically cut making the hybrid seeds available at affordable prices.

Hybrid Cotton Seed Production

• It is estimated that around 8500 tons of hybrid seeds of Cotton are required annually involving Rs.320 crore.
• As male sterile based hybrids are yet to over come initial problems, the conventional hybrid cotton seed production has to satisfy this huge demand.
• For a farmer, hybrid seed production in Cotton is a profitable enterprise – provided skilled labours are available.

The detailed steps involved are hybrid cotton seed production are

• Procure the parent seeds from recognised government office and register with certifying agency.
• Sow the male and female parents separately. Female parents are sown at a minimum of 120 cm x 90 cm spacing and male are sown at 90 x 60 cm spacing. Flowers from one male plant is sufficient to pollinate atleast 20 female plants.
• Manure the plots with 15 tons FYM. Apply a basal dose of 75 Kg.N, 75 Kg. P2O5 75 Kg K2O /ha. Remaining 75 Kg. N can be given in 3 splits).
• Take up regular sprays of plant protection as recommended.
• It is necessary to identify the female flowers about to open and emasculate (Removal of male parts & corolla) them and tag them by coloured ribbon. Emasculation should be done between 4 PM to 6 PM.
• Next day between 9 AM to 11 AM, these flowers are crossed by bringing male flowers in physical contact with them. Only such male flowers – which are in anthesis should be used.
• It is necessary to cover the crossed female flowers with butter paper covers for 4-5 days and later removed.
• The process is continued as and when female flowers are ready for crossing.
• On a daily basis, such female flowers which are ready to be crossed but actually not crossed for many practical reasons must be removed from plant.
• At the end of crossing programme harvest the kapas from crossed bolls separately (they are togged) and keep the kapas separately. Uncrossed bolls should be harvested separately (if any uncrossed bolls are remaining).
• Procurement agency will collect the kapas, gin them, test them and certify them and pay the farmer.

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