A single-nucleotide polymorphism in PvPW1 encoding β-1,3-glucanase 9 is associated with pod width in Phaseolus vulgaris L.

Pod width influences pod size, shape, yield, and consumer preference in snap beans (Phaseolus vulgaris L.). In this study, we map PvPW1, a quantitative trait locus associated with pod width in snap beans, through genotyping and phenotyping of recombinant plants. We identify Phvul.006G072800, encoding the β-1,3-glucanase 9 protein, as the causal gene for PvPW1. The PvPW1^G3555 allele is found to positively regulate pod width, as revealed by an association analysis between pod width phenotype and the PvPW1^G3555C genotype across 17 bi-parental F₂ populations. In total, 97.7% of the 133 wide pod accessions carry PvPW1^G3555, while 82.1% of the 78 narrow pod accessions carry PvPW1^C3555, indicating strong selection pressure on PvPW1 during common bean breeding. Re-sequencing data from 59 common bean cultivars identify an 8-bp deletion in the intron linked to PvPW1^C3555, leading to the development of the InDel marker of PvM436. Genotyping 317 common bean accessions with PvM436 demonstrated that accessions with PvM436²⁴⁷ and PvM436²²⁷ alleles have wider pods compared to those with PvM436²¹⁹ allele, establishing PvM436 as a reliable marker for molecular breeding in snap beans. These findings highlight PvPW1 as a critical gene regulating pod width and underscore the utility of PvM436 in marker-assisted selection for snap bean breeding.