Impacts of Gama Irradiations on the Development New Mutants of Stevia rebaudiana Bertoni

Abstract

Stevia rebaudiana Bertoni is known for its production of sweet glycosides, an alternative to sugar. The cultivation of stevia in Malaysia is hampered because- it produces flowers at an early stage under Malaysia's photoperiod condition, thus leading to poor leaf yield for sweetener extraction. Additionally, there has been low breeding work for suitable cultivars. Thus, the impact of Gama irradiation in developing new Stevia mutants was studied. Seeds of MS012 were collected and exposed to gamma irradiation using a gamma cell in UKM, Malaysia to determine the LD50. The seeds were packed into 21 parts; one part served as the control and the others were subjected to varying gamma irradiation grays of 100 to 2000 grays. Irradiated seeds were sown for germination under the red light for 15 days. The LD50 was determined by plotting a simple regression graph of plant height against irradiation grays. Results revealed LD50 was 55 grays. The number of germinated seeds differed with respect to doses. Genetic analysis showed four types of chlorophyll mutants were induced: Albina, Chlorina, Xantha and Xantha-Viridis. Frequency and spectrum analysis revealed that Chlorina has the highest occurrence at 33.03%. Two classical novelties: (i) M1RAAMBO/03, and (ii) M2 RAAMBO/04 were developed.