Asian Plant Research Journal

Green gram (Vigna radiata L.) is a nutritionally rich and versatile crop widely used for food and feed. However, its genetic improvement through conventional breeding is constrained by self-pollinating flowers and limited genetic diversity, making traditional methods inefficient for yield enhancement. Induced mutagenesis offers a viable alternative to create novel genetic variability. This study aimed to establish the mean lethal dose (LD₅₀) of ethyl methane sulphonate (EMS) and gamma irradiation in three green gram varieties (Shwe Toe-009, MAS-1, and Yezin-9). Nine EMS concentrations (0.00% [control], 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35 % and 0.40%) and seven gamma radiation doses (0 Gy [control], 200 Gy, 400 Gy, 600 Gy, 800 Gy, 1000 Gy and 1200 Gy) were applied. Results showed a progressive decline in germination and survival percentages with increasing mutagen doses. Probit analysis revealed that EMS-treated samples exhibited similar LD₅₀ values across all varieties, reflecting its uniform biochemical mode of action (alkylation of DNA bases). Gamma-irradiated samples displayed genotype-dependent LD₅₀ values, attributable to varietal differences in seed morphology, antioxidant capacity, and DNA repair efficiency against radiation-induced chromosomal damage. The predicted LD₅₀ ranges were 400–650 Gy for gamma rays and 0.4% for EMS, providing optimal doses for balancing mutation induction with plant survival. These findings enable large-scale mutagenesis programs to generate diverse mutant populations for green gram improvement.