Vietnam: Various grades and types of rice for sale in a market, Hanoi (photo)

Rice is the seed of the monocot plants Oryza sativa (Asian rice) or Oryza glaberrima (African rice). As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in Asia and the West Indies. Rice is the most important grain with regard to human nutrition and caloric intake, providing more than one fifth of the calories consumed worldwide by the human species. There are many varieties of rice and culinary preferences tend to vary regionally. For example in India, there is a saying that 'grains of rice should be like two brothers, close but not stuck together', while in the Far East there is a preference for softer, stickier varieties. Because of its importance as a staple food, rice has considerable cultural importance. For example, rice is first mentioned in the Yajur Veda and then is frequently referred to in Sanskrit texts. Rice is often directly associated with prosperity and fertility, therefore there is the custom of throwing rice at weddings.