Origin and Introduction
The soybean, a native of eastern Asia, is one of the oldest crops of that area and is considered to be a vital grain crop. The soybean belongs to the family Leguminosae, subfamily Papilionideae, and the genus Glycine. Glycine is composed of two subgenera, glycine and soja. The cultivated soybean, Glycine max (L.) Merr., and its wild counterpart, Glycine soja, are now classified as species of the subgenus soja. Glycine max, Glycine soja, and most species of the subgenus glycine are diploid (2n=40). Soybean was first domesticated in China from the 11th to the 7th century B.C as understood by pictographic evidence of the ancient Chines word “shu”