Genotype dependent somatic embryogenesis and regeneration from leaf base cultures of sorghum bicolor

Abstract

A simple and reproducible protocol for callus induction and regeneration of plantlets from leaf base cultures of agronomically important Indian cultivars of Sorghum bicolor (L.) Moench (296 B and RS 585) has been developed. A strong genotype dependent response was observed and the genotype 296 B was found to be the most responsive as compared to the other genotypes tested. Cultures were raised from the III, IV and V leaf bases, excised from 12-day-old in vitro raised plantlets and cultured on Callus Induction Medium (CM). Callus initiation took place after 10-14 days of culture. The explants were maintained on this medium for 30-35 days, after which they were transferred to Regeneration Medium (RM). Histological examination indicated that somatic embryogenesis was prevalent in the leaf base cultures and the embryos started to germinate after 15-20 days of transfer to RM. Plantlets with complete shoot and root system have been raised with as many as 30 plantlets regenerating from a single explant. These plantlets could be easily separated from one another and transferred to culture tubes for faster growth and development . Later, individual plants numbering more than 50 were transferred to pots containing soil: soilrite (1:1) for hardening. A high regeneration frequency of up to 40% could be obtained in the genotype 296 B followed by 10.8% in the genotype RS 585 and 7.8% in C 43.