Genetic variability for susceptibility to seed coat mechanical damage and relationship to end‐use quality in kidney beans

Abstract

AbstractKidney beans (Phaseolus vulgaris L.) have strict market specifications for seed and end‐use quality. One major quality concern is the appearance of cracks, also termed checks in the seed coat caused by mechanical damage occurring during harvest and postharvest handling. Genetic variability for seed coat checks (SCCs) has not been well characterized in kidney beans. The objectives of this study were (1) to test an existing screening method for easy assessment of seed coat mechanical damage, (2) to explore the genetic variability for mechanically induced seed coat damage in kidney bean and its relationship to seed coat thickness, (3) to characterize the relationship of SCC to end‐use quality, and (4) to identify potential germplasm resources for genetic improvement. A collection of dark red, light red, and white kidney beans were grown over 2 years and harvested with two threshing methods to mimic mild and severe treatments of mechanical damage. Belt threshing produced mild damage, and combine threshing produced severe damage. Seed coat thickness was not correlated with SCC of the combine‐threshed beans but was negatively correlated with the belt‐threshed beans at r = –0.33. Seed moisture content played an important role in SCC. Higher SCC severity scores resulted in lower canning quality appearance scores (r = –0.51). The SCC severity score of combine‐threshed seeds can be used as a selection factor in variety improvement for resilience to mechanical damage. Genotypes with low SCC severity score were identified for breeding initiatives.