Culture and regeneration of mesophyll-derived protoplasts of sorghum [Sorghum bicolor (L.) Moench]

A protocol for plant regeneration from mesophyll/protoplasts of sorghum [So rghum bicolor (L.) Moench] was developed. The yield of intact protoplasts, their subsequent divisions and regeneration were genotype-dependent. The ge notype 296B was always more responsive than IS 32266. For 296B, the sixth l eaf from 18-day-old plants kept in dark for 2 days before harvesting was fo und to be the most suitable source of viable protoplasts, The first divisio n was observed 10-12 days after plating, and the second division after 12-1 4 days. The maximum plating efficiency was 4.8% in 296 B, followed by 2.48% in IS 32266. Microcolonies were visible after 25-30 days, and microcalli a fter 60-75 days. Whole plants were obtained after 6-8 weeks of culture of m icrocalli on MS medium containing 0.2 mg l(-1) kinetin and 2 mg l(-1) BAP. The frequency of regeneration in 296B and IS 32266 was 12.80% and 10.58%, r espectively. Ten plants transferred to pots in the glasshouse established w ell. The seeds collected from glasshouse-grown plants were sown in the fiel d where plants were grown to maturity.