We have been using the technique of slab-gel electrophoresis (see Gorman and Kiang, 1977, 1978; Kiang, 1981; Kiang and Gorman, 1983, for methods) to study genetic diversity in G. max and G. soja. In last year's Soybean Genet-ics Newsletter, we reported the accession-specific zymogram types (zymogram types are equivalent to phenotypes) observed in 253 named cultivars (maturi-ty groups 00-IV) for 15 enzyme systems (Gorman et al., 1982b). We have been studying the genetic basis for the differences between these zymogram types.