The raising of plants by man for his use; deliberate propagation of a species primarily for its fruit, seed, leaf, or fiber. Cultivation greatly increased and stabilized man's food supply. The change from food gathering to food production has been called the Neolithic Revolution, and was one of the most important advances in human development. The first among Old World crops were wheat and barley, developed as cultivated species c 7th millennium BC. To these were added oats and rye in Europe, millet in Asia, and sorghum in Africa. In the Americas, the process was equally slow. First crops included beans, cotton, gourds, maize, manioc, potatoes, and squashes.