This report is a catalog of genetic. releases among 258 soybean cultivars released by public agencies during 1945-88. Its purpose is to provide soybean breeders with a practical guide for the selection of good parental material and for the preservation of genetic diversity in their breeding programs. To develop this guide, we used pedigree analysis, a common technique in plant breeding. Based on the concept of allelic identity by descent, this approach uses the familial relationships among cultivars to quantify the probability of two cultivars having identical genes at a random locus.