Influence of nitrogen and phosphorus on induction embryogenic callus of sorghum

Crown and leaf slices of in vitro plantlets of a non-flowering Vetiveria zizanioides from Java were used to induce compact calli and to regenerate plantlets. The influence of different growth regulators (2,4-dichlorophenoxy acetic acid, 6-benzylaminopurine), sucrose concentrations (10–100 g l⁻¹), cultivation in light or dark, and cultivation time on callus induction medium (6 or 12 weeks), on the induction of compact callus and the subsequent regeneration of plantlets was studied. Up to 75% of crown slices cultured on modified Murashige and Skoog medium supplemented with 2.26 μM 2,4-dichlorophenoxy acetic acid, 2.22 μM 6-benzylaminopurine and 75 g l⁻¹ sucrose developed compact callus. For subsequent regeneration of plantlets, callus induction in the light for 6 weeks on the callus induction medium containing 10 g l⁻¹sucrose, and subsequent transfer to the regeneration medium, was the best procedure, regenerating plantlets on around 60% of the crown or leaf slices, with up to 100 plantlets per slice. We have compared the efficiency of the above mentioned procedure with several other methods to regenerate plantlets. Our findings indicate that the procedure developed in this study was best in regenerating plantlets for the used vetiver variant. This revised version was published online in June 2006 with corrections to the Cover Date.