Postharvest seed coat darkening in pinto bean ( Phaseolus vulgaris ) is regulated by P sd , an allele of the basic helix‐loop‐helix transcription factor P

Pinto bean ( Phaseolus vulgaris ) is one of the leading market classes of dry beans that is most affected by postharvest seed coat darkening. The process of seed darkening poses a challenge for bean producers and vendors as they encounter significant losses in crop value due to decreased consumer preference for darker beans. Here, we identified a novel allele of the P gene, P sd , responsible for the slow darkening seed coat in pintos, and identified trait‐specific sequence polymorphisms which are utilized for the development of new gene‐specific molecular markers for breeding. These tools can be deployed to help tackle this economically important issue for bean producers.