The presence of the 120,000 dalton soybean seed lectin (SBL) is controlled by a simple dominant gene designated Le (Orf et al. , 1978). A recent immunological survey of the USDA soybean [Glycinemax (L . ) Merr . ] collection indicated that 2,646 of 2,664 lines are Le (St ahlhut and Hymowitz , 1980), and an analogous study of the USDA G. soja Sieb. & Zucc . collection indicated that 285 of 559 lines contain SBL (Stahlhut et al., 1981 ). SBL preparations from seeds of the soybean lines 'Beeson', D68-127, ' Disoy', 'Forrest', 'Harosoy 63', and T-247 apparently are identical; electrophoresis under denaturing conditions separated each lectin into two types of subunits, and isoelectric focusing resolved each into a complex mixture of isolec tins (Su et al. , 1980) .