Genetic Diversity in Natural Populations of Wild Soybean in Iwate Prefecture, Japan

To study the genetic structure of wild soybean (Glycine soja Sieb. & Zucc.) populations, seeds were systematically sampled from four natural populations growing along banks of the Kitakami River in Iwate Prefecture, Japan. Fifteen enzymes plus one nonenzyme protein (soybean trypsin inhibitor, Ti) representing 42 loci were examined by gel electrophoresis. We observed 38.1% polymorphism, an average of 1.55 alleles per locus, an average expected heterozygosity of 0.115, and an average gene diversity of 0.112 ± 0.036. The average outcrossing rate of 2.3% is similar to 2.4% estimated in cultivated soybean (G. max(L.) Merr.]. Calculated genetic diversity shows 0.074 and 0.302 between- and within-population diversity, respectively. The coefficient of differentiation among populations is 0.197.