Last year we reported that sterility in three male sterile mutants (Ames, Harosoy, and Urbana) was controlled by a single recessive gene at the ms1 locus (Palmer and Winger, 1975). Our results with the Urbana male sterile are in agreement with those of Cooper and Boerma (1975). In allelism tests with the North Carolina ms1 mutant, several of the sterile testcross progeny had a few seeds.
Palmer, R. G. and Heer, Hollys E.
"Research Notes: Polyploids Among the Progeny from Male Sterile (ms1ms1)
Soybean Genetics Newsletter: Vol. 3
, Article 18.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol3/iss1/18