Optimizing gamma radiation and EMS doses for mutation in Brassica rapa L. var. yellow Sarson

Abstract

This study evaluated the effects of gamma radiation and ethyl methane sulphonate (EMS) on seed germination and mortality to optimize mutagenic doses for mutation breeding in Brassica rapa L. var. Yellow sarson. Results indicated that low to moderate gamma radiation doses (200-400 Gy) maintained high germination rates (>80%) with manageable mortality (~15-17%), making them suitable for inducing mutations while preserving seed viability. EMS treatment caused a substantial reduction in germination, reflecting its strong mutagenic potential but higher toxicity. Combination treatments and higher gamma doses resulted in excessive mortality and reduced germination, suggesting these are less optimal. The control group established baseline germination and mortality in the absence of mutagenesis. These findings emphasize the importance of dose standardization to balance effective mutation induction with seed survival. This study supports the use of lower to moderate mutagen doses for efficient mutation breeding, providing valuable insights for Brassica crop improvement programs.