STRUCTURE estimation of the wild soybean genetic structure. NE, wild soybean from north-east China; NC, wild soybean from the Huang-Huai Valley; SC, wild soybean from south China; R, wild soybean from the Russian Far East; K, wild soybean from South Korea; J, wild soybean from Japan. (A) Genetic structure of 40 populations covering most of the distribution area in China based on 20 microsatellites, with K = 2 and (B) K = 3. (C) Genetic structure of 231 representative individuals covering the whole distribution area in East Asia based on 56 microsatellites, with K = 2. (D) Genetic structure of representative individuals from East Asia except the Huang-Huai Valley based on 56 microsatellites, with K = 3.