Effect of hormones, explants and genotypes in in vitro culturing of sorghum

In vitro culturing of sorghum is very much influenced by genotypes, explants, media composition and hormones. Among the genotypes tested CO 25 was found to show high frequency of callus induction and regeneration. Regeneration efficiency of embryogenic calli from CO 25 was found to be greater (88-98%) than that of calli derived from other explants (Immature inflorescence, Mature embryo and Shoot tips) of different genotypes (CO 26, TNS 586 and CO-S-28). Out of the different media tried for callus induction and regeneration of sorghum, I6 medium + kinetin 0.5 mg l-1 + 2,4-D 2 mg l-1 showed high frequency of embryogenic calli from immature embryo of CO25. Regeneration medium I6 + Kinetin (1.0) + NAA (0.5) + casein hydrolysate at levels of 250 mg l-1 and 500 mg l-1 was found to best medium composition for regeneration. An efficient protocol has been developed from suitable explant and genotype for callus induction, regeneration of sorghum and thus to produce transgenic plants for biotic and abiotic resistance. Keywords: In vitro culture, Sorghum, explants, genotypes, hormones Received: 12 March 2009 / Received in revised form: 18 July 2009, Accepted: 5 August 2009, Published online: 21 September 2009