Identification of quantitative trait loci for bean paste color in the adzuki bean (Vigna angularis)

Abstract

Bean paste color is one of the most important quality traits in adzuki beans (Vigna angularis). The present study was aimed at identifying quantitative trait loci controlling bean paste color and its associated seed color using recombinant inbred lines (RILs) crossed between cv. ‘Murasakisayaka’ (superior bean paste color) and cv. ‘Erimoshozu’. RILs and parental cultivars were grown over two years and in two locations in Hokkaido, Japan. Seed coat color and boiled bean color were evaluated using the L*C*h color space. A total of 36 PCR-based molecular markers, including 34 insertions/deletions, CAPS, and derived CAPS markers, were developed through re-sequencing data of the parents. Using these DNA markers, seven linkage groups (LGs) covering a total length of 363.6 cM were constructed. The hue angle of the boiled bean (BBH) of the bean paste color of ‘Murasakisayaka’ was consistently lower than that of ‘Erimoshozu’ across four trials. For seed coat color, 2 QTLs for L*, 4 QTLs for C*, and 3 QTLs for h were identified on LGs 3, 4, 7, 8, 10, and 11. For boiled bean color, a single QTL for L*, 3 QTLs for C*, and 4 QTLs for h were identified on LGs 1, 3, 10, and 11. These QTL findings should facilitate gene isolation and breeding application for the improvement of the bean paste quality of adzuki bean cultivars.