A Note on Rice Plant History, Cultivation and Characteristics

Rice introduction

Rice is a semi aquatic annual grass belonging to the genus Oryza and has two cultivated and 22 wild species. The cultivated species are Oryza sativa and O. glaberrima. O. sativa is grown all over the world while Oryza glaberrima has been cultivated in West Africa for about 3500 years. There are more than 120,000 varieties of cultivated rice. Cultivated rice is diploid (2n=24) and belong to AA genome. O. sativa has two subspecies O. sativa ssp. indica and O. sativa ssp. japonica. A less prominent intermediate O. sativa ssp. javonica is also available.

History of Rice

Rice was domesticated more than 10,000 years ago is possibly one of the oldest domesticated species. Huke and Huke (1990) observes that the domestication of rice ranks as one of the most important developments in history, for this grain has fed more people over a longer period of time than has any other crop.
Rice is the staple cereal for more than 50% people (~3.25 billion) around the world, cultivated in about 9% of the earth's arable land, which is the largest single use of land for producing food. Rice provides 25 to 85 percent of the calories in the daily diet and 15% of per capita protein.

In Asia, where rice is the major energy providing food, it accounts for 50-80% of daily caloric intake, especially among the poor. Unlike other major cultivated grains like wheat and corn which are also used for feeding livestock, rice is exclusively used for human consumption.

Rice Cultivation

With China, India and Indonesia producing the most of the world’s rice, Asia accounts for over 90% of the world's production of rice. Only 6-7% of the world's rice crop is traded in the world market. Production of rice in The United States accounts to 1.5% of the world's production, with Arkansas, California and Louisiana producing 80% of the U.S. rice. Thailand, Vietnam, China and the United States are the world's largest exporters.

Also Read: What is Plant Breeding and Genetics

Rice is the only cereal that can be grown for long period in standing water. Even though predominantly semi-aquatic, rice is grown under many different conditions and production systems, including upland and dry conditions. 57% of the world’s rice is grown on irrigated land, 25% on rainfed lowland, 10% on the uplands, 6% in deepwater, and 2% in tidal wetlands. The flooded rice paddy sustains rich aquatic biodiversity, providing a home for fish, plants, amphibians, reptiles, mollusks, and crustaceans.

Characteristics of Rice

Rice has many characteristics, making it useful in various ways to be included in cereals, snack foods, brewed beverages, flour, oil, syrup, flakes and religious ceremonies. Rice grains can be short, medium and long or waxy (sticky) or non-waxy. Some are aromatic, some are colored including brown, red, purple and black and some are of medicinal value. The variation in characteristics makes one variety more popular in one region of the world than another.