Plant regeneration in pigeonpea [Cajanus cajan (L.) Millsp.] by organogenesis

A method for regenerating pigeonpea [Cajanus cajan (L.) Millsp.] plants has been developed using distal cotyledonary segments of mature seeds as explants. A large number of shoot buds were induced directly from explants of genotypes T-15-15 and GAUT-82-90 when cultured on six different basal media fortified with 22.2 μM N⁶-benzylaminopurine, 2.3 μM kinetin, and 271 μM adenine sulfate. The shoot buds developed into shoots when they were subcultured on the same medium but with one-tenth concentrations of cytokinins and adenine sulfate. The shoots elongated by subculturing first two to three times on Murashige and Skoog (MS) basal medium supplemented with 2.22 μM N⁶-benzylaminopurine and 0.54 μM α-naphthaleneacetic acid or on half-strength MS medium containing 2.89 μM gibberellic acid, and then once on the same medium without growth regulators. Elongated shoots were rooted with 80-85% efficiency on MS medium with 4.92 μM indole-3-butyric acid and the plantlets were transferred for hardening. Plants survival in pots was 70-75%. This method may be useful for improving the crop through genetic manipulations.