Development of new cowpea (Vigna unguiculata) mutant genotypes, analysis of their agromorphological variation, genetic diversity and Population structure

Abstract

Cowpea is one of the most important legume grain in the SubSaharian region of Africa used for human consumption and animal feeding but its production is hampered by biotic and abiotic constraints raising the need to broaden its genetic basis. For this purpose, the seeds of two cowpea varieties Melakh and Yacine were respectively irradiated with 300 and 340 Gy. The developed mutant populations were agromorphologically characterized from M5 to M7 while the genetic diversity of the last were evaluated using 13 ISSR markers. Based on agromorphological characterization, variation of flower color, pod length, seed coat color and seed weight with respectively 78.01, 68.29, 94.48 and 57.58% heritability were recorded in the mutant lines. PCA analyses allowed to identify the elite mutants based on their agromorphological traits while Pearsons correlation results revealed a positive correlation between yield component traits. Three subpopulations were identified through STRUCTURE analyses but assignment of the individuals in each group was improved using DAPC. Analysis of Molecular Variance revealed that the majority (85%) of the variance rather existed within group than among (15%) group. Finally, our study allowed to select new promising mutant genotypes which could be tested for multi local trials to evaluate their agronomic performance.