Establishment of a Suitable Protocol for Clonal Propagation of Stevia (Stevia rebaudiana) and Creating its Advanced Lines using Gamma-Ray

Abstract

A suitable protocol was developed for in vitro clonal propagation of Stevia rebaudiana Bertoni from shoots tip and nodal explant. Experiments were conducted to standardize the culture media composition with plant hormone for multiple shoot proliferation and rooting for obtaining plantlets with uniform characteristics like the mother plant in terms of growth and habits. The best response towards multiple shoot regeneration was observed from nodal explants on Murashige and Skoog (MS) basal media fortified with 3.0 mg/L Benzyl amino purine (BAP). In this combination, an average of 14 shoots were regenerated from the shoot tip and 16 shoots were regenerated from nodal explant. Multiple shoots were increased up to two to three times higher when they were sub-culture in the same media combination. Plantlets produced profuse rooting within 10 to 16 days after transfer to MS supplemented with different concentrations of Indole-3-butyric acid (IBA), Alpha naphthyl acetic acid (NAA) and Indole-3-acetic acid (IAA) (0.5-2.5 mg/l). Best root development was obtained in MS containing 1.5 mg/l IBA. Rooted plantlets were transferred to soil for hardening. About 90% of plantlets were successfully established to the field condition. For the induction of the mutation, radio sensitivity tests were performed by determining lethal dose-50 (LD50) after irradiating the explants by gamma ray. The LD50 was 45 gray (Gy) for shoot tip explants whereas 55 gray (Gy) for nodal explants. Some morphological changes occurred in the treated explants which is significant for induction of mutation.

 J. of Sci. and Tech. Res. 6(1): 99-107, 2024