Gene T is involved in black pigmentation and w1 in the presence of t is involved in imperfect black pigmentation (Bernard and Weiss, 1973). Tis a phenolase gene resulting in quercetin formation and brown pubescence (Buttery and Buzzell, 1973); W is a flower and hypocotyl-color gene (Hartwig and Hinson, 1962). Thin layer chromatography shows two major 'spots' involved in black pigmentation of soybean seed coats.
Buzzell, R. I. and Buttery, B. R.
"Research Notes : Genetics of black pigmentation of soybean seedcoats/hila,"
Soybean Genetics Newsletter: Vol. 9
, Article 11.
Available at: https://lib.dr.iastate.edu/soybeangenetics/vol9/iss1/11