Mutagenesis is a well-known technique for introducing new variants into crop plants. In the present study, M2 populations were generated in the cowpea (Vigna unguiculata (L.) Walp.) variety CO7 using gamma irradiation. The M2 progeny were used to investigate the effectiveness of the gamma irradiation doses and examined for the agronomic traits. The genomic variation present in the mutants and their parents was analysed using five SCoT markers. Marker analysis revealed a total of 87 amplicons and among these, 20 amplicons showed polymorphism. The highest numbers of amplicons were observed at SCoT10 (39), while the lowest number of amplicons was produced by SCoT09 (07). The percentage of polymorphism ranged from 18.18% to 28.57%, with an average of 21.12%. Polymorphic information content (PIC) values ranged from 0.197 to 0.345. Analysis of Molecular Variation (AMOVA) showed 12% and 88% between the genotypes and within the genotypes respectively. The constructions of 4 clusters were identified through Unweighted Pair Group Method with Arithmetic Mean (UPGMA) dendrogram tree based on the genetic distance deduced from SCoT marker analysis. Analysis of the genetic relatedness between parent and mutants through Principal Coordinate Analysis (PCoA) revealed two main groups. The present study concludes that the genetic variability induced by gamma irradiation and inherited in the next generations. This research investigation supports that gamma irradiation alters the growth and yield traits, which is helpful for generating the cowpea improvement.

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.