An entry consisting mostly of plants having little to no seed set was found amidst the breeding material of Dr. Walter R. Fehr (Iowa State University) in 1975. The entry was descendent from germplasm population AP6(Sl)Cl, which was described by Fehr and Ortiz (1975). Investigations have revealed that partial male sterility was the primary cause leading to reduced seed set (Stelly, 1979).

Information regarding cross pollinating insects in soybeans has been mainly restricted to honeybees. Erickson (1975) reported that attractiveness of soybeans to honey bees appeared to be heritable. Jaycox (1970) reported on the ecological relationships between honey bees and soybeans.

Several abnormal nodulation reactions in soybeans are known. These range from a complete lack of nodules, caused by the non-nodulating gene (Williams and Lynch, 1954) to plants with normal-appearing nodules (Vest et al., 1973), but low nitrogen fixation as exemplified by the 'Peking'-strain T23 combination. The purpose of the study reported here was threefold.