Among the first plants that were cultivated and domesticated, the characteristics associated with ease of transportation and storage was highly desired. The Gramineae species, and most importantly, their domestic variants, such as the cereals, (included in this type of plants) represent the staple food in different parts of the world. Their origin and domestication appear connected to the origin of the main civilizations. So, each one of the three main crops (rice, maize and wheat) have been associated with one important civilization: wheat with Sumer or Egypt in the Mediterranean region; rice with Chinese civilization in Asia; and maize with the Olmec and Maya civilizations in America.
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