EVALUATION OF INDUCED GENETIC VARIABILITY IN BLACK TURTLE BEAN (PHASEOLUS VULGARIS L.) USING GAMMA RAYS, EMS, AND THEIR COMBINATION IN PETRI PLATE GERMINATION ASSAY

Induced mutagenesis is an essential method to increase genetic variability in crop species. This study evaluates the effects of gamma radiation and Ethyl Methane Sulphonate (EMS) on seed germination, root and shoot length, and fresh biomass of Black Turtle Bean (Phaseolus vulgaris L.) under controlled Petri plate conditions. Seeds were exposed to gamma rays (200-600 Gy) from a Cobalt-60 source and various EMS concentrations (0.1-0.6% v/v), individually and in combination. The treated seeds were germinated in triplicate with 25 seeds per replicate to assess their physiological responses. Results showed a clear dose-dependent decrease in germination percentage, root and shoot length, and biomass, with higher doses producing significant reductions. The combined treatments exhibited more pronounced adverse effects than individual treatments. The findings highlight the mutagenic sensitivity of Phaseolus vulgaris and provide guidance for determining optimal doses in mutation breeding programs aimed at genetic improvement.