Genetic diversity and population structure analysis in popular cowpea (Vigna unguiculata (L.) Walp) cultivars

Genetic diversity and population structure of 21 cowpea (Vigna unguiculata (L.)Walp) popular genotypes were evaluated using simple sequence repeat (SSR) molecular markers. A set of 144 primer pairs were used; out of which 71 gave polymorphic amplicons. A total of 184 amplicons with an average of 2.562 alleles per polymorphic marker were observed. The average effective number of alleles (Ne) was 1.928 alleles per genotype. The presence of a higher Shannon's information index (I) of 0.651 indicates higher diversity in the given set of cowpea lines. The total accessions were stratified into 2 groups (K=2) in population structure analysis. In phylogenetic analysis, 3 major clades were formed. The results give insight into existing diversity in the popular cowpea cultivars and a framework for future studies aimed at the selection of parental lines for cowpea genetic improvement programmes.