In 1975 we selected green, partially sterile plants in farmers' fields when the normal plants had dropped their leaves and were ready for harvest . Seeds were harvested from the off-type plants and planted in the greenhouse (1975-76). The resulting plants which we called "F1's" were nonnal.
Hadley, H. H.; Openshaw, S. J.; and Pennell, J. C.
"Research notes: Sterility mutants in soybeans,"
Soybean Genetics Newsletter: Vol. 5
, Article 7.
Available at: https://lib.dr.iastate.edu/soybeangenetics/vol5/iss1/7