Comparison of in vitro regeneration efficiency of leaf explants in response to different cytokinins and assessment of genetic uniformity of regenerated plants of Solanum surattense Burm.f.

Abstract

An efficient, genetically stable and rapid regeneration system via multiple shoot formation was developed for an endangered medicinal herb Solanum surattense. Leaves were cultured on MS medium supplemented with different concentration of cytokinins; 6-benzylaminopurine (BAP), kinetin (Kn), thiadiazuron (TDZ), zeatin and inorganic phosphate (iP) alone or in combinations. Among five cytokinins used, TDZ (0.1 mg/l) gave the maximum regeneration response (35 shoot buds per explant), with 100% regeneration efficiency. Comparative regeneration efficiency of cytokinins was in the following order: TDZ > zeatin > iP > BAP > Kn and the comparative ratio was 6:4:3:2:1. Highest
frequency of adventitious shoot bud induction (54 shoot buds per explant) was achieved on combination of TDZ (0.1 mg/l) and BAP (1 mg/l). Combinations of cytokinins were more effective for shoot bud regeneration as compared to cytokinin alone. Best root formation was observed on Murashige and Skoog (MS) medium supplemented with 1 mg/l indole-3-acetic acid (IBA). The rooted plantlets were hardened gradually and resulted in a production of more than 80% plantlets. The
efficiency of auxins for root organogenesis was in the following order: IBA > IAA > NAA > PAA. Genetic stability of regenerated plants was analyzed using random amplified polymorphic DNA (RAPD) markers.

Keywords: Solanum surattense, adventitious shoot buds, genetic fidelity, random amplified polymorphic DNA, thiadiazuron