High Frequency Clonal Multiplication of Stevia rebaudiana Bertoni, Sweetener of the Future

The present study describes an efficient, rapid clonal propagation protocol for a natural sweetener herb, Stevia rebaudiana. Shoot tips and nodal segments were inoculated on Murashige and Skoog’s medium [MS 1962] containing different cytokinin and auxin alone or in combinations. Shoot tips were proved to be better in comparison to nodal segments having higher rate of shoot induction and multiplication. Best shoot multiplication from both the explants was obtained on MS medium supplemented with 5.0 µM 6benzyladenine (BA) and 1.0 µM a-naphthalene acetic acid (NAA). A maximum of 19.60 shoots per shoot tip and 16.00 shoots per nodal segment with an average shoot length of 4.70 and 4.28 cm were obtained. Subculturing of the regenerating tissue on the optimized treatment showed further enhancement in shoot proliferation without any decline in multiplication rate. The regenerated microshoots showed the most efficient rooting on half strength MS medium augmented with 2.5 µM indole-3-butyric acid (IBA). Plantlets went through a hardening phase prior to ex vitro transfer and established in earthen pots containing garden soil and green manure (1:1). The established plantlets were uniform and identical to mother plant with respect to growth characteristics and vegetative morphology.