Plant Architecture Traits Show Co-localized Signals in Common Bean Durango Diversity Panel

Common bean (Phaseolus vulgaris L.) shows many domestication syndromes like other cultivated crops. One of the major differences between the wild and the cultivated species is plant architecture. The cultivated forms show more erect growth habit compared to the wild types that are mainly creeper/climbers. This characteristic is important in bean production due to its impact on harvest practices and disease incidence. The type II growth habit (indeterminate erect) is favored because it lowers harvest costs while reducing disease incidence due to higher air flow in between rows and minimum pod contact with the soil.  To discover the genomic regions associated with plant architecture, a genome wide association study (GWAS) was conducted using the Durango Diversity Panel (DDP). Traits such as stem shear test, plant length, canopy height, canopy width, growth habit, and lodging were measured in North Dakota for 145 DDP genotypes. Re-sequencing of the DDP genotypes up to 6x coverage yielded 2.1 million SNPs with minor allele frequency of 5% and greater for GWAS. Significant co-localized GWAS signals were detected for these inter-related traits. A GWAS peak on Pv07 was in common among all the traits. Pv11 also had a consistent peak among all the traits except canopy width. The major GWAS signal for lodging and canopy height were on Pv04 and Pv07, respectively. Growth habit encompassed both these signals as its major peaks. This study provides a starting point to discover the genes that affect the plant architecture in the Durango race in common bean.