Thursday, 4 April, 2002, 19:22 GMT 20:22 UK
Rice: Food for the world
Rice is more than just a food crop
The draft DNA sequences of rice (Oryza sativa) will help scientists breed new, more productive varieties of the plant.
- Rice is a type of grass, with narrow, tapered leaves and grows from about 60 to 180 centimetres (about 2 to 6 ft) tall. Its edible grain is the primary food for over half the world's population.
- There are about 20 known species of rice but thousands of subspecies.
Asian rice is known scientifically as Oryza sativa and African rice as Oryza glaberrima.
- African and Asian rice varieties are grown with their roots submerged in water, which allows the plants to more easily take up the nutrients they need to flourish.
- Rice farmers constantly have to battle a range of diseases and pests. The most common diseases stem from the fungi sheath blight and rice blast, while the stalk borer is a common insect pest.
- According to Shinto belief, the Emperor of Japan is the living embodiment of Ninigo-no-mikoto, the god of the ripened rice plant.
- Rice is used for a variety of non-food products. The inedible rice hull is used as fuel, fertiliser, and insulation, while the straw from the leaves and stems is used as bedding for animals and for weaving roofs, hats, baskets, and sandals.
- Archaeological evidence clearly shows that rice was cultivated in Thailand at least 6,000 years ago.
- Scientists at many institutions, notably the International Rice Research Institute (IRRI) in the Philippines, are using both conventional and modern breeding methods to create new, higher-yielding varieties. These new plants require less fertiliser, resist insects and diseases, tolerate poor soil, require less irrigation, and photosynthesise more efficiently.
- World rice production totals nearly 600 million tonnes. Asian farmers produced about 90% of the total, with two countries, China (including Taiwan) and India, producing more than 50% of the total crop.
- In Bangladesh, Cambodia, Indonesia, Laos, Myanmar, Thailand and Vietnam, rice provides 55-80% of total calories consumed.
- Less than 5% of world rice production is traded internationally. Major rice exporters are Thailand, the United States, Vietnam, Pakistan, and India.
The BBC is not responsible for the content of external internet sites
Top Sci/Tech stories now:
Links to more Sci/Tech stories are at the foot of the page.