Role of PGR on in vitro shoot propagation in Cyamopsis tetragonoloba L. (Taub.): a drought tolerant grain legume

Abstract

An efficient in vitro mass propagation protocol for Cyamopsis tetragonoloba L. (Taub.), a drought tolerant multipurpose grain legume, has been developed. A comparative range of cytokinins have been investigated for multiple shoot induction and plant regeneration with cotyledonary node, node and shoot tip explants. Four weeks exposure with thidiazuron (TDZ) containing medium, prior to transfer to BA supplemented medium was sufficient to induce maximum number of shoots. In descending order regarding shoot formation, the four different cytokinins at the optimum concentration could be ranked as TDZ, BA, Kn and 2iP. Optimum multiple shoot induction occurred in MS medium containing 5.0 μM (TDZ) or 10.0 μM (BA) where an average of 14.6 ± 0.67 or 7.8 ± 0.73 shoots, respectively, were produced in cotyledonary node explant after 8 weeks of incubation. Elongated shoots were rooted on half strength MS medium containing 5.0 μM (IBA) with about 45 % efficiency, the plantlets thus obtained were transferred to thermocol cups containing sand:soil (3:1) mixture and placed in a hardening room. Survival rate of plantlets in pots was more than 80 % and all the regenerated plants appeared morphologically normal.