Rice is one of the world's most important staple crops and a major part in the diet of more than half the world’s population, rice also has many medicinal uses.
Oryza sativa, rice, is a genus of perennial grass in the Poaceae (grass family) that originated in India, Thailand, and southern China, was domesticated and diversified in ancient times, and is now cultivated in wet tropical, semi-tropical, and warm temperate areas around the world for the production of its cereal grain. Rice is one of the two most important cereal crops world for human consumption; the other is wheat, Triticum species. (Corn, Zea mays, is produced in larger amounts, but a sizable portion of it is used for livestock feed and making ethanol for biofuel). Rice is cultivated on an estimated 3% of the world’s agricultural land, and serves as a primary source of calories for over half the world’s population. Rice has also been important as a model system in plant biology, and is the first plant species for which the genome has been fully mapped.
Oryza sativa has hundreds of cultivars with different grain color, size, and shape, as well as environmental tolerances and seasonality—the types are generally categorized as valley rice, upland rice, spring rice, and summer rice. It is generally grown in fields that are flooded for part of the growing season—whether from irrigation (the majority of cultivation), rainfed or floodplain systems--which help reduces competition from other plants, among other benefits; some upland varieties can be grown without flooding, but they account for only 4% of rice cultivated worldwide.Rice is thought to have been domesticated in India and brought to China by 3,000 B.C. It was cultivated in Babylon and the Middle East by 2,000 years ago, and spread to the Europe during medieval times. The FAO estimates that the total commercial harvest of rice in 2010 was 672.0 million metric tons, harvested from 153.7 million hectares. China and India were the leading producers, followed by Indonesia, Bangladesh, and Vietnam; the U.S. is ranked 10th. Within the U.S., Arkansas accounts for the largest share of rice cultivation, followed by California, Louisiana, Mississippi, Missouri, and Texas.
In PAmiRDB, 738 miRNA from O.sativa are scanned against viral genomes, in order to get insight into viral genome and miRNA intractions.