Rapid plant regeneration and analysis of genetic fidelity in micropropagated plants of Vitex trifolia : an important medicinal plant

An efficient in vitro regeneration protocol of a valuable medicinal plant, Vitex trifolia has been successfully established using nodal segments as explants. Three different cytokinins (BA, Kn, 2iP) and auxins (NAA, IAA, IBA) in different concentrations and combinations, evaluated as supplements to Murashige and Skoog’s medium showed to have a marked influence on the regeneration output. Among all the single cytokinin treatments MS medium supplemented with 5.0 μM BA produced the maximum number of shoots yielding 8.20 ± 0.37 shoots per explant with 4.8 ± 0.43 cm shoot length after 8 weeks of culture. Combined with low auxin concentrations, all the three cytokinins at their optimal concentrations synergistically enhanced the regeneration credentials. However, MS medium enriched with 5.0 μM BA and 0.5 μM NAA yielded the best possible regeneration in the species with a regeneration percentage of 97.33 ± 2.67 % and amounting to 16.80 ± 0.58 shoots per explant with 6.20 ± 0.25 cm mean shoot length at the end of 8 weeks in culture. Ex vitro rooting of in vitro derived microshoots was achieved by 20 min 500 μM IBA treatment followed by transfer to thermocol cups containing sterile soilrite. A 95 % plantlets survived acclimatization procedure to the field. Genetic conformity of the regenerated plants was established through RAPD. All the bands visualized on agarose gels were monomorphic with that of the donor plant indicating the clonal nature of the regenerants.