Soybean, Glycine max, is an important crop throughout the world. Soybean is a source of food, oils—both culinary and industrial—and animal feed. In addition, soybean products can be found in plywood, particleboard, printing inks, soap, candy, cosmetics, and antibiotics.

Cultivated soybean and its wild ancestor, Glycine soja, are members of the legume family, Fabaceae. Legumes are particularly valuable because, in conjunction with symbiotic bacteria, they fix atmospheric nitrogen and they are excellent sources of protein, with soybeans containing the highest level of this nutrient.

The cultivated soybean plant is an erect, bushy annual. Plants produce clusters of three to fifteen purple or white flowers that develop into pubes-cent (fuzzy) pods, usually containing two to four seeds. Soybean seeds vary in size and are commonly yellow in color, but can also be green, black, or brown. Soybean varieties are classed into thirteen maturity groups according to their...