Plant regeneration from scutella of immature embryos of diverse sorghum genotypes

We compared two different culture media for high frequency callus induction and plant regeneration from cultured immature embryos (excised scutella) of 14 sorghum genotypes. Embryogenic calli were induced in 10-15 days after the embryos were plated on LS medium with 0.25 mg l^-1 zeatin and 0.5 mg l^-1 2,4-D. For induction of embryogenic callus, this media was better than the other with 2,4-D alone. Regeneration was achieved by transferring embryonic calli to MS medium containing 2 mg l^-1 NAA, 0.5 mg l^-1 BAP and 0.1 mg l^-1 GA₃. Both callusing and regenerating ability varied (10-100%) among the genotypes. Popular seed parents 296 B and BTx 623 showed 100% callus induction and regeneration. The anatomical studies on embryogenic calli derived from scutellum revealed 4-6 pro-embryos from each scutellum, with secondary embryos initiating around the primary ones after a month under culture. The above protocols are appropriate for use of immature embryos to genetically transform wide range of sorghum genotypes.