In the 1961 Uniform Soybean Test II, seeds with a tan-saddle pattern were found among normally yellow-seeded 'Harosoy' plants. The tan-saddle pattern was found to breed true, and is now designated k2. The Harosoy line from which k2 was derived is designated T239 in the Genetic Type Collection.
Shoemaker, Randy C. and Palmer, Reid G.
"Research Notes : Genetic analysis of a chlorophyll deficient, tan-saddle mutant,"
Soybean Genetics Newsletter: Vol. 9
, Article 39.
Available at: https://lib.dr.iastate.edu/soybeangenetics/vol9/iss1/39