Mutation breeding plays a vital role as a source of genetic diversity to improve plant growth and development. Green gram (Vigna radiata (L.) R. Wilczek) “Vamban 2” variety was selected for this investigation. The doses applied to the healthy seeds of green gram were 100 Gy, 200 Gy, 300 Gy, 400 Gy, 500 Gy, 600 Gy, 700 Gy and 800 Gy and non-treated seeds were kept as control throughout this study. A lethal dose (LD50) was observed at 500 Gy, whereas seedling length, fresh and dry weight decreased as the applied doses increased while compared to the control. Irradiated seedlings showed a decreased content of chlorophyll a compared to Chlorophyll b and increased carotenoid content compared to the control. Biochemical characteristics such as reducing sugar, starch, protein, amino acid and proline content were increased and noted maximum at 800 Gy. Antioxidants and lipid peroxidation (MDA) increased gradually along with increasing doses. FTIR analysis exhibited maximum functional groups at 600 Gy and ESR data showed ample hyperfine range of structure at 500 Gy, 600 Gy and 700 Gy. This investigation found considerable alterations in morphology, photosynthetic pigment, biochemical characteristics and antioxidant analyses, which suggest an idea to select an appropriate dose of gamma irradiation in green gram for successive breeding program.

The present study was aimed to evaluate the effect of gamma irradiation on green gram through chlorophyll mutation frequency, leaf mutation frequency, mutagenic effectiveness and efficiency and principal component analysis. Eight different types of chlorophyll mutants, namely albino, aurea, striata, tigrina, xantha, chlorina, viridis, xanthaviridis and variegated were observed at different doses of gamma irradiation in M2 generation. Albino showed the highest frequency percentage (0.229) followed by Viridis (0.163) and Xantha (0.131) and the highest frequency was noted at 500 Gray (Gy). Though, chlorophyll mutants can be lethal in nature, they increase genetic variability and induce new traits. Leaf mutant is another key indicator for induced mutations that induce leaf morphology changes and the highest frequency was noted in 500 Gy. Among the mutagenic treatments, the mutagenic effectiveness shows the maximum at 100 Gy and efficiency shows at 500 Gy. This indicated that low to moderate doses are more effective for induced mutation. This was also confirmed by Principal Component Analysis (PCA) results, which specified that gamma irradiation of 500 Gy indicated that the first five principal components were attributed to 70.82% total variability of traits studied. From this, the experimental finding evidently showed that 500 Gy of gamma irradiation, an optimum dose, resulted in considerable variation in all the parameters analyzed.