EFFECT OF GAMMA RADIATION ON MORPHOLOGICAL AND GENETIC VARIATION IN REGENERATED PLANTLETS Catharanthus roseus L. (G) Don

Catharanthus roseus L. (G) Don, commonly known as Madagascar periwinkle, is an important medicinal plant receiving much attention from researchers. This plant is a rich source of terpenoid indole alkaloids (TIAs). The gamma radiation and somaclonal variation may provide suitable methods for genetic changes to increase medicinal components of C. roseus. In the present study, 30 and 60 (Gy) gamma rays were irradiated on seeds. C. roseus seeds were cultured in Murashige and Skoog (MS) medium in three different groups, 0 Gy (control) 30, and 60 Gy gamma irradiations. Morphological characteristics of regenerated plantlets were measured for surface area of leaves, stem length, root length, and fresh weight. The genetic variations were evaluated using nine inter-simple sequence repeats and 25 sequences related amplified polymorphism markers. Morphological results showed a significant difference between studied groups in leaf surface and twisted leaf in 60 Gy irradiated plantlets. The analysis of molecular variance revealed the significant genetic difference among groups. STRUCTURE analysis showed genetic variability both within and among groups. Using the NJ tree analysis, the plants studied were categorized into three distinct groups, which were supported by principal coordinate analysis (PCoA). In conclusion, gamma irradiation produced morphological and genetic changes in C. roseus regenerated in vitro plantlets providing to be a suitable method for further mutation breeding in periwinkle.