In 1976, a plant was selected from the M3 generation of some 'Essex' soybeans that had been irradiated with neutrons and grown at the Eastern Virginia Research Station, Warsaw. The plant had a green stem and reduced seed set. The progeny row grown the following year had all normal appearing plants.
Buss, G. R.
"Research Notes : Inheritance of a male-sterile mutant from irradiated Essex soybeans,"
Soybean Genetics Newsletter: Vol. 10
, Article 33.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol10/iss1/33