Effect of different doses of gamma rays on Indian mustard (Brassica juncea L.) genotypes

Mutation breeding through gamma irradiation is a widely used technique to induce genetic variability and improve crop traits. This study aimed to evaluate the effects of different doses of gamma radiation on mustard (Brassica juncea L.) genotypes DRMR 1165-40 and RADHIKA. The experiment was conducted in a Randomized Block Design with three replications during the rabi season 2023-2024 at the Field Experimentation Centre, Department of Genetics and Plant Breeding, SHUATS, Prayagraj. Mustard seeds were exposed to gamma radiation at doses of 5 kR (T1), 10 kR (T2), 15 kR (T3), 20 kR (T4), and 25 kR (T5), along with a control (T0). Results indicated that lower radiation doses (5 kR) significantly improved germination percentage, survival rate, plant height, siliqua per plant, seeds per siliqua, seed yield per plant, oil content, and test weight. In contrast, higher doses (22 kR) adversely affected these traits, leading to reduced plant vigour, delayed flowering and maturity, and lower yield attributes. The findings suggest that gamma radiation induces physiological and genetic modifications, influencing growth and reproductive traits. Lower radiation doses can be effectively utilized for trait enhancement in mustard without compromising plant health, whereas higher doses may cause detrimental effects. These results align with previous reports on mutation breeding in oilseeds and provide valuable insights for optimizing radiation doses in crop improvement programs. Further molecular and biochemical analyses are recommended to elucidate the mechanisms underlying radiation-induced variations.