Rice, (Oryza sativa), edible starchy cereal grain and the grass plant (Poaceae) by which it is produced. Roughly one-half of the world population, including virtually all of East and Southeast Asia, is wholly dependent upon rice as a staple food. It is best suited to regions which have high humidity, prolonged sunshine and an assured supply of water. The major soil groups where rice is grown are riverine alluvium, red-yellow, red loamy, red sandy, mixed red, black, medium and shallow black soils.