Title : Genetic diversity and population structure of cowpea [Vigna unguiculata (L.) Walp.] from Europe and Africa using DArT and SNP markers
Cowpea (Vigna unguiculata) is an important grain legume well adapted to the dry regions with the added benefit of enhancing soil fertility. Cowpea makes an important contribution to the nutritional security of small farmers in tropic and sub-tropic regions mainly in Africa. International and national research institutions have been making progress concerning cowpea conventional breeding. However, modern breeding, based on molecular tools with a genotyping capability that quickly generates results, will allow faster breeding decisions than conventional procedures. This study reports the genotyping of 97 cowpea landraces from Europe and Africa using high throughput DArTseq and next-generation sequencing technologies. A total of 61,221 silicoDArT and 38,889 SNP markers were found. After screening with quality control parameters that include ³95% reproducibility, 31,420 silicoDArT and 11,050 SNP markers were used for subsequent analysis. These markers had a mean Polymorphic Information Content (PIC) value of 0.14 and 0.17, respectively for silicoDArT and SNP. The model-based Bayesian cluster analysis in STRUCTURE visualized the genetic structure of the populations under examination. SilicoDArT and SNP analysis clearly separated genotypes of distinct origins, such as those from Portugal and from Mozambique. Similar to silicoDArT markers, SNP markers also produced two major clusters. There is more genetic diversity in the accessions from Mozambique than in the accessions from Portugal. Our study highlights silicoDArT and SNP markers as valuable tools for cowpea genetic variation assessment. The presented results will help researchers and breeders to select and introduce new cowpea germplasm resources for future exploitation in breeding programs.