Biological Effect of gamma irradiations on in vitro culture of Stevia rebaudiana

Current investigation was carried out to study effects of gamma irradiations on in vitro culture of S. rebaudiana. The dosages used were 5, 10, 15, 20, 25 and 30 kR (Kiloradians). Explants were selected from plants, derived from gamma irradiated seeds were subjected for callus induction, callus proliferation and somatic embryogenesis on the MS medium fortified with 2.5 mg/l 2,4-D. Differences in the morphology and growth rate of callus were recorded. High dose of Gamma irradiation showed necrosis of explants. The somatic embryogenesis percent decreased with increasing dosage of gamma radiations. Somatic embryo generation was significantly affected by higher doses of gamma rays. This study also indicates that plants produced from seeds irradiated with 5 - 10 kR gamma rays influences callus induction and growth. Explants obtained from plants, grown from gamma irradiated seeds with higher doses such as 25 kR and 30 kR delays callus induction. The data on Days to callus induction, growth rate and somatic embryogenesis, indicate that low dose of gamma radiation is effective for the production of variability in Stevia plants.