Development of a Protocol for In-vitro Regeneration of Stevia rebaudiana Bertoni

The experiment was conducted to find out an effective combinations and concentrations of plant growth regulators for in vitro regeneration of Stevia rebaudiana Bertoni, a medicinally important, zero-calorie value, sweet tasted and an antidiabetic herb. Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of BAP and NAA were used for shoot regeneration using shoot tip as explant. The highest shoot regeneration percentage (83.33%) was obtained from the MS medium supplemented with 1.0 mg/l BAP + 2.0 mg/l NAA followed by 72.92% of shoot regeneration from MS medium supplemented with 3.0 mg/l BAP + 3.0 mg/l NAA. The lowest percentage (29.17%) of shoot regeneration was observed in MS medium with 0 mg/l BAP + 1.0 mg/l NAA. Significant numbers of healthy and vigorous shootlets were proliferated showing normal phenotypes. The in vitro proliferated shoots were inoculated on MS medium supplemented individually with 0, 1.0, 6.0 mg/l IBA for root initiation. Among the treatments used for root initiation, the highest percentage (75%) of root formation was observed in MS medium supplemented with 6 mg/l IBA + 1.0 mg/l BAP + 2.0 mg/l NAA followed by 71.43% in MS medium with 6 mg/l IBA + 3.0 mg/l BAP + 3.0 mg/l NAA. In contrast, the lowest percentage (14.28%) of root formation was obtained in MS medium supplemented with 6 mg/l IBA + 0 mg/l BAP + 1.0 mg/l NAA. For mass production of healthy Stevia plantlets, MS media supplemented with 1.0 mg/l BAP + 2.0 mg/l NAA, in combination with MS media supplemented with 6 mg/l IBA + 1.0 mg/l BAP + 2.0 mg/l NAA could be used for further proliferation of the plantlets for commercial purpose.