Common beans (Phaselous vulgaris L) represents the most widely cultivated of the Phaseolus species. It is a nutritious crop that provides protein, minerals and dietary fiber. Black beans are one of the most popular market classes, with large consumption in the U.S., Mexico, and Central America. Black beans are distinguished from other common beans classes by high anthocyanins in the seed coat which impart the black color. The water soluble anthocyanins make the canning process for black beans challenging. Canning requires several steps, including soaking and boiling. Although the canning process makes beans edible, it also alters the physical and chemical properties of the seeds. In the case of black beans, soaking seeds accelerates anthocyanin loss which lighten the seeds and produce a canned product with poor appearance. Genetic variability for color retention can be exploited to select and incorporate superior genetics for this trait. The objective of this research was to assess the genotypic and phenotypic diversity for a set of 69 black bean breeding lines and cultivars from the major U.S. public bean breeding programs. Each of the lines was grown in field trials in 2013 and 2014. They were evaluated for agronomic, canning characteristics and anthocyanins profile of raw and canned seed. Color retention as determined by a trained sensory panel on a scale of 1 to 5 was highly variable and ranged from 1.4 to 4.5. Delphinidin-3-glucoside was identified as the dominant anthocyanin with the highest concentration among black bean genotypes. The anthocyanin malvidin-3-glucoside was found to be retained after canning more than the other two anthocyanins. Genome wide association analysis was conducted to determine genomic regions responsible for color retention and canning quality in black beans that were genotyped with 5398 SNP markers. A region on Pv05 at 39Mb was associated with color retention and was polymorphic candidates for MAS.
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