Genome‐wide Association Analysis for Drought Tolerance and Associated Traits in Common Bean

Abstract

A genome-wide association study explored the genetic ba - sis of variation for drought tolerance and related traits in a Middle American diversity panel comprising 96 common bean ( Phaseolus vulgaris L.) genotypes. The panel was grown under irrigated and rainfed conditions and single nucleotide polymorphism (SNP) data were used to explore the genetic diversity and ancestry of the panel. Varying levels of ad - mixtures and distinctly divergent individuals were observed. Estimations of genome-wide heterozygosity revealed that, on average, greater diversity is present in individuals with Me - soamerica (3.8%) ancestry, followed by admixed individuals (2.3%). The race Durango had the lowest level of heterozy - gosity (1.4%). We report 27 significant marker–trait associa - tions based on best linear unbiased predictors. These asso - ciations include seven markers for shoot biomass at harvest under irrigation and five markers under rainfed conditions on P. vul garis ( Pv ) chromosome Pv 11, two markers for shoot biomass at flowering under irrigation on Pv 02 and Pv 08, two markers for seed size under irrigated and rainfed conditions on Pv 09, seven markers for lodging score under irrigation on Pv 02 and Pv 07, one marker for leaf elongation rate on Pv 03 and one for wilting score on Pv 11. Positional candidate genes, including P h v u l . 011G1 0 2 7 0 0 on Pv 11, associated with wilting, were identified. The SNP ss715639327 marker was located in the exon region of the P vS I P1;3 gene, which codes for an aquaporin associated with water movement in beans. Significant quantitative trait loci identified in this study could be used in marker-assisted breeding to accelerate genetic improvement of drought tolerance in common bean.