An efficient micropropagation protocol for Stevia rebaudiana

The present study was conducted to develop an efficient and reproducible mass multiplication protocol in stevia. The shoot-tip and nodal segments were used as explants. The survival percentage of nodal explants was 100%, when explants were treated with HgCl₂ (0.1%) for 3 minutes along with bavistin (0.2%) and streptocyclin (0.2%) for 45 minutes. The nodal and shoot-tip explants were best responded to MS medium supplemented with 2.0 mg/l BAP. Among the different media used, MS medium supplemented with 2.0 mg/l BAP showed the maximum shoot induction (98.0%) in 4.7 days and (74.0%) in 7.1 days using nodal and shoot tip explants, respectively. BAP alone was found to be better for establishment of aseptic culture of stevia instead of combinations of different cytokinins and auxins. MS basal medium supplemented with 0.3 mg/l BAP + 0.3 mg/l Kin + 0.1 mg/l NAA was proved to be the best with 34.9 shoots/explant developed from nodal and shoot-tip explants after 30 days on culture medium. Maximum rooting (90±7.75%) was observed on the half MS medium supplemented with 0.5 mg/l NAA with 21.2 roots per shoot in 7.4 days. The roots formed in medium without hormone were not healthy. Rooted shoots were separated individually and transferred to plastic bag containing sand, soil and vermi compost in ratio of 1: 1: 1 with 100% survival. The hardened plants were transferred to field using recommended agronomic practices.