Bernard (1971) reported on two major genes, E1 and E2, that affect the time of flowering and maturity of soybeans. Buzzell (1971) reported another maturity gene, E3; the recessive allele did not respond to fluorescent-daylength treatment. Kilen and Hartwig (1971) reported a recessive gene for a similar character in southern varieties.
Bernard, R. L. and Buzzel, R. I.
"Research Notes: U.S. Regional Soybean Laboratory, USDA-ARS, University of
Illinois, Urbana-Champaign, and Agriculture Canada,"
Soybean Genetics Newsletter: Vol. 2
, Article 14.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol2/iss1/14