Molecular genetic analysis of US and Chinese soybean ancestral lines

Most of the U.S. soybean [Glycine mar (L.) Merr.] ancestral lines were intr oduced from China, but nothing is known of the genetic relationships among the ancestors of modern U.S. and Chinese cultivars. The objectives of this research were to measure the variation among the major ancestors of U.S. an d Chinese cultivars, to establish the genetic relationships among these U.S . and Chinese soybean ancestral lines, and to determine the relationship be tween geographical origin and genetic diversity. Genomic DNA from these lin es was characterized by random amplified polymorphic DNA (RAPD) with 35 sel ected decamer primers. On the basis of the presence or absence of amplified DNA fragments, simple matching coefficients were used to calculate genetic similarities between pairs of lines. Cluster analyses generally separated the ancestral gene pools of the USA and China. Clusters reflected the geogr aphical origin of the lines. Large differences exist between northern U.S. and Chinese ancestral lines and central and southern Chinese ancestral line s. ne pattern of diversity found within the U.S. and Chinese ancestors can aid breeders in selecting parental lines to more efficiently exploit the di versity found in these two major gene pools.