60Co gamma ray induced mutants of cowpea and assessment of genetic variability by SCoT marker

Abstract

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.