# Genome-Wide Association Study for Drought Tolerance in Cowpea (Vigna unguiculata (L.) Walp.) at Seedling Stage Using a Whole Genome Resequencing Approach

## TL;DR

This study identifies genetic regions in cowpea linked to drought tolerance, helping improve crop resilience.

## Contribution

The study identifies specific genomic loci associated with drought tolerance in cowpea seedlings using GWAS.

## Key findings

- A cluster of 196 SNPs on chromosome 5 is linked to trifoliate leaf chlorosis tolerance under drought.
- A strong GWAS peak on chromosome 1 is associated with unifoliate leaf chlorosis tolerance.
- 25 SNPs on chromosomes 1, 3, 5, and 11 are significantly associated with plant greenness under drought stress.

## Abstract

Despite the fact that cowpea is one of the most drought-tolerant legumes, some genotypes with a high yield under well-watered conditions have been shown to be susceptible to drought stress, thus requiring further improvement. The objectives of this study were to conduct a genome-wide association study (GWAS) for drought tolerance in cowpea. A total of 331 cowpea genotypes were evaluated for drought tolerance. After SNP filtering, 5,884,299 SNPs were used to conduct GWAS using BLINK. The results showed: (1) a significant GWAS peak defined by a cluster of 196 significant SNPs and mapped on a 210 kb region of chromosome 5 was identified to be a good locus candidate for tolerance to trifoliate leaf chlorosis under drought stress in cowpea, (2) a strong GWAS peak was found towards the end of chromosome 1 and this peak was a good candidate locus for tolerance to unifoliate leaf chlorosis under drought stress in cowpea, and (3) a total of 25 SNPs located on chromosomes 1, 3, 5, and 11 were significantly associated with plant greenness under drought stress. This study provides a better understanding of the molecular genetics of drought tolerance in cowpea and the findings can be expanded to other crop species.