Callus induction

The present study reports that the increased level of boric acid in the induction medium enhanced shoot bud induction and plant regeneration in Indian Barley cultivars. Primary cultures were raised on MSB5 medium supplemented with 20.7 M picloram and subsequently subcultured and regenerated on medium with 12.47 M & 0.2 M picloram respectively. Concentration of boric acid was modified at different stages of culture. Higher level of boric acid in the induction medium not only improved shoot but induction but also plant regeneration in later stages of cultures. Regeneration frequency of 100% with 3.4 folds more number of plantlets was achieved when H3BO3 concentration in the induction was raised to 1.0 mM (10 times than in MS) and reduced to 0.1 mM (Normal MS level) in the subculture and regeneration medium. The increased level of H3BO3 in the induction medium also proved better for other recalcitrant Indian varieties.

The effect of calcium chloride on callus induction and plant regeneration from cultured immature embryos of Indian barley (Hordeum vulgare L. cultivar BL-2) and seeds of indica rice (Oryza sativa L. cultivar Pusa Basmati-1) has been investigated. Murashige and Skoog's medium containing Gamborg's medium vitamins and 20.7 M, 12.47 M & 0.2 M picloram was used for callus induction, subculture and plant regeneration in barley cultures respectively. Rice callus was induced on Murashige and Skoog's medium supplemented with 11.31M 2,4-dichlorophenoxyacetic acid and subsequently regenerated on MS medium containing 2.68 M 1-naphthaleneacetic acid and 8.87 M 6-benzylaminopurine. The basal media at different stages of culture were supplemented with different levels of calcium chloride (0 to 29.9 mM). Calcium chloride was found to be essential for plant regeneration. Higher level of calcium chloride at various phases of culture prior to regeneration was beneficial for regeneration of both barley and rice cultures. The optimum requirement was same for the two plants though for both the plants this level varied with the phases of culture. Regeneration frequency up to 100% with 2-2.5 folds higher number of regenerated plantlets was achieved when calcium chloride concentration in the induction and subculture media was raised to 14.95 mM and reduced to 2.99 mM in the regeneration medium.