Potential of meta-Topolin (mT) in improved in vitro regeneration of Feronia limonia (L.), Swingle

Abstract

The present study was designed to investigate the stimulatory effect of different doses (0.5–10.0 µM) of meta-Topolin (mT), a new aromatic cytokinin on in vitro shoot induction and proliferation of cotyledonary (CN) explants obtained from 30 days old axenic seedlings of a tropical fruit tree, Feronia limonia of family Rutaceae. A range of two cytokinins benzyl adenine (BA) and meta-Topolin (mT) was tested for multiple shoot induction and proliferation on MS medium. Out of two cytokinins evaluated, mT proved more effective and 5.0 µM gave best response for inducing maximum shoots (10.60 ± 0.51) with mean length (1.72 ± 0.09 cm) in 90% cultures after 12 weeks. The equimolar concentration of BA induced a lesser number of shoots. Among the tested concentrations, 5.0 µM mT in combination with 0.50 µM α-naphthalene acetic acid (NAA) yielded maximum mean shoot numbers (26.24 ± 0.18) and average shoot length (2.87 ± 0.02 cm) after 12 weeks of culture. The most efficient in vitro rhizogenesis (90%), was achieved on ½ MS medium enriched with 5.0 µM Indole-3-butyric acid (IBA) with mean root number (3.20 ± 0.20) and length (4.52 ± 0.10 cm) after four weeks of culture. The regenerated plantlets were successfully acclimatized and hardened off in Soilrite™ with 86% survival rate. The plantlets were transferred to earthen pots where they showed normal growth. This appears to be the first report available on the use of mT for regeneration of F. limonia and was found to be more effective than BA.