Study of Callus Induction and Somatic Embryogenesis in Cotton

Optimization of regeneration methods in cotton is necessary to improve and Successful production of transgenic cotton cultivars by tissue culture technique. This study was conducted to determine the genotypic effect on callus induction in cotton using 3 genotypes (Coker349, 4-S-4 and C1211) and Coker 312 selected and a study was carried out in Cotton Research Institute of Gorgan using a factorial experiment based on completely randomized design with three replications in 2011. Explants of hypocotyls and cotyledons of these genotypes were isolated and placed on two cotton callus media MSB (MS medium with Gamborg vitamins-B5), MSB1 medium supplemented with 0.1 mgl-1 2,4-D, 0.1 mgl-1 kinetin, 0.75 gl-1 MgCl2 and MSB2 medium supplemented with 1 mgl-1 NAA. Cultures incubated at 28±2ºc under a light intensity of approximately 2000 lx with 16/8 light/darkness photoperiod for callus induction. In medium containing 2,4-D and Kinetin, 4-S-4 explants of hypocotyls and cotyledons produced callus earlier than Coker349, Coker312 and C1211. The percentage of callus production for 4-S-4 cultivar in two callus media was higher than other genotypes. Callus production from hypocotyls in two media and cotyledon in MSB1 medium for all genotypes showed the highest size of calli most of which were embryogenic. Explants of cotyledon for all genotypes were produced root and no produce callus. For embryogenesis induction and maturation of embryos, produced calli were transferred onto MSB medium supplemented with 0.75 gl-1 MgCl2 and 1.9 gl-1 KNo3. Induced Somatic embryos were transferred on embryo germination medium and plantlets produced for 4-S-4, Coker 349 and Coker 312 genotypes.