Flavonoid constituents of seed coats of Vicia faba (Fabaceae) in relation to genetic control of their color

Flavonoid aglycones were identified from Vicia faba L. seed coats corresponding to eight genetically determined colors. Myricetin predominates over quercetin in beige, black, brown, green, red, and violet seeds. Kaempferol is present in substantial amounts only in spotted seeds. White seeds have only trace amounts of quercetin and kaempferol and are the only ones without proanthocyanidins. Flavones of the apigenin type occur in all colors but white. Anthocyanins (malvidin, delphinidin, petunidin, and cyanidin glycosides) are present only in violet seeds and are obviously responsible for their color. The dark colors of black, brown, and red seeds apparently result from unidentified polymers. It is concluded that the two loci, a and b, proposed by Ricciardi et al. (1985) as the sites of genetic control of seed-coat color, control the amount and type of flavonoids produced: locus a that of flavonoid monomers (flavonols, etc.) and locus b that of flavonoid polymers (condensed tannins).