ABSTRACT
Soybean (Glycine max [L.] Merr.) and its wild progenitor (G. soja Sieb. and Zucc.) belong to the genus Glycine, subgenus soja. Both G. soja and G. max are annual and predominantly self-pollinating (Hymowitz 2004). G. soja is endemic to East Asia including China, far eastern Russia, Japan, and Korea. It is believed that G. max was domesticated from G. soja about 4,500 years ago in China (Qiu et al. 2011). The domesticated soybean was introduced from China to Europe in 1737, to North America in 1765, and to South America in 1882 (Chang 1989). At present, modern soybean is an important economical crop for food, feed, and fuel, grown worldwide. In addition, although the nomenclature and classification of G. gracilis Skvortzow, a unique type of soybean bearing morphologically intermediate characteristics between typical G. soja and G. max accessions, was always controversial, many scientists believe that these semi-wild soybeans may serve as important materials for understanding the evolutionary history of soybean (Skvortzow 1927, Hymowitz 1970, Broich and Palmer 1980, Wang and Li 2011).
