Marker-Trait Association Analysis of Seed Traits in Accessions of Common Bean (Phaseolus vulgaris L.) in China

Seed weight and seed size are the key agronomic traits that determine yield in common bean. To investigate the genetic architecture of four seed traits (100-seed weight, seed length, seed width, and seed height) of common bean in China, marker-trait association analysis of these seed traits was performed in a nationwide population of 395 common bean accessions using 116 polymorphic SSR markers. The four seed traits were evaluated in six trials across three environments. Seed size varied among the environments. Population structure was evaluated based on SSR markers and phaseolin, which divided the accessions into two main subpopulations representing the two known gene pools. Seed weight and seed size had a strong relationship with population clustering. In addition, in a Genome-wide association studies (GWAS), 21 significantly associated markers were identified for the four seed traits with two models, namely, general linear model (GLM) and mixed linear model (MLM). Some markers had pleiotropic effects, i.e., controlled more than one trait. The significant quantitative trait loci identified in this study could be used in marker-assisted breeding to accelerate the genetic improvement of yield in common bean.