![White, Brown, Red & Wild rice](https://upload.wikimedia.org/wikipedia/commons/7/7b/White%2C_Brown%2C_Red_%26_Wild_rice.jpg)
Rice is the
seed of the
grass species ''
Oryza sativa'' (Asian rice) or less commonly ''
Oryza glaberrima'' (African rice). The name
wild rice is usually used for species of the genera ''
Zizania'' and ''
Porteresia
''Porteresia coarctata'' is a species of grass in the family Poaceae, native to India, Sri Lanka, Bangladesh, and Myanmar.
''Porteresia coarctata'' is considered by some botanists to be the only species in the genus ''Porteresia''. Other autho ...
'', both wild and domesticated, although the term may also be used for primitive or uncultivated varieties of ''
Oryza
''Oryza'' is a genus of plants in the grass family. It includes the major food crop rice (species ''Oryza sativa'' and ''Oryza glaberrima''). Members of the genus grow as tall, wetland grasses, growing to tall; the genus includes both annual an ...
''.
As a
cereal grain, domesticated rice is the most widely consumed
staple food
A staple food, food staple, or simply a staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for a given person or group of people, supplying a large fraction of energy needs and ...
for over half of the world's
human population
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
,
[Abstract, "Rice feeds more than half the world's population."] especially in
Asia and
Africa. It is the agricultural
commodity
In economics, a commodity is an economic good, usually a resource, that has full or substantial fungibility: that is, the market treats instances of the good as equivalent or nearly so with no regard to who produced them.
The price of a comm ...
with the third-highest worldwide production, after
sugarcane
Sugarcane or sugar cane is a species of (often hybrid) tall, Perennial plant, perennial grass (in the genus ''Saccharum'', tribe Andropogoneae) that is used for sugar Sugar industry, production. The plants are 2–6 m (6–20 ft) tall with ...
and
maize.
Since sizable portions of sugarcane and maize crops are used for purposes other than human consumption, rice is the most important food crop with regard to human nutrition and caloric intake, providing more than one-fifth of the
calories consumed worldwide by humans. There are many varieties of rice and culinary preferences tend to vary regionally.
![Oryza sativa of Kadavoor](https://upload.wikimedia.org/wikipedia/commons/9/94/Oryza_sativa_of_Kadavoor.jpg)
The traditional method for cultivating rice is flooding the fields while, or after, setting the young seedlings. This simple method requires sound irrigation planning but reduces the growth of less robust weed and pest plants that have no submerged growth state, and deters
vermin. While flooding is not mandatory for the cultivation of rice, all other methods of
irrigation require higher effort in
weed and
pest control during growth periods and a different approach for fertilizing the soil.
![Single grain of rice](https://upload.wikimedia.org/wikipedia/commons/c/ce/Single_grain_of_rice.png)
Rice, a
monocot, is normally grown as an
annual plant
An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...
, although in
tropical areas it can survive as a
perennial and can produce a
ratoon
Ratooning is the agricultural practice of harvesting a monocot crop by cutting most of the above-ground portion but leaving the roots and the growing shoot apices intact so as to allow the plants to recover and produce a fresh crop in the next se ...
crop for up to 30 years. Rice cultivation is well-suited to countries and regions with low
labor costs
A wage is payment made by an employer to an employee for work done in a specific period of time. Some examples of wage payments include compensatory payments such as ''minimum wage'', ''prevailing wage'', and ''yearly bonuses,'' and remunerat ...
and high
rainfall, as it is labor-intensive to cultivate and requires ample water. However, rice can be grown practically anywhere, even on a steep hill or
mountain area with the use of water-controlling terrace systems. Although its parent species are native to Asia and certain parts of Africa, centuries of trade and exportation have made it commonplace in many cultures worldwide. Production and consumption of rice is estimated to have been responsible for 4% of global
greenhouse gas emissions in 2010.
Characteristics
The rice plant can grow to tall, occasionally more depending on the variety and soil fertility. It has long, slender leaves long and broad. The small
wind-pollinated flowers are produced in a branched arching to pendulous
inflorescence long. The edible seed is a grain (
caryopsis) long and thick.
Food
Cooking
The
varieties of rice
This is a list of rice cultivars, also known as rice varieties. There are several species of grain called rice. Asian rice (''Oryza sativa)'' is most widely known and most widely grown, with two major subspecies (''indica'' and ''japonica'') and ov ...
are typically classified as long-, medium-, and short-grained. The grains of long-grain rice (high in
amylose) tend to remain intact after cooking; medium-grain rice (high in
amylopectin) becomes more sticky. Medium-grain rice is used for sweet dishes, for ''
risotto'' in Italy, and many rice dishes, such as ''
arròs negre
''Arròs negre'' (, es, arroz negro) is a Valencian and Catalan dish made with cuttlefish (or squid) and rice, somewhat similar to seafood paella. Some call it ''paella negra'' (''"black paella"''), although it is traditionally not called a pae ...
'', in Spain. Some varieties of long-grain rice that are high in
amylopectin, known as Thai Sticky rice, are usually steamed. A stickier short-grain rice is used for ''
sushi'';
the stickiness allows rice to hold its shape when cooked.
Short-grain rice is used extensively in Japan, including to accompany savoury dishes.
Short-grain rice is often used for
rice pudding.
Instant rice differs from
parboiled rice in that it is fully cooked and then dried, though there is a significant degradation in taste and texture. Rice flour and
starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...
often are used in
batters and breadings to increase crispiness.
Preparation
Rinsing rice before cooking removes much of the
starch
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets ...
, thereby reducing the extent to which individual grains will stick together. This yields a fluffier rice, whereas not rinsing yields a stickier and creamier result.
Rice produced in the US is usually fortified with vitamins and minerals, and rinsing will result in a loss of nutrients.
Rice may be soaked to decrease cooking time, conserve fuel, minimize exposure to high temperature, and reduce stickiness. For some
varieties, soaking improves the texture of the cooked rice by increasing expansion of the grains. Rice may be soaked for 30 minutes up to several hours.
Brown rice may be soaked in warm water for 20 hours to stimulate
germination
Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...
. This process, called
germinated brown rice
Germinated brown rice (GBR; ko, 발아현미(發芽玄米), bara-hyeonmi, ja, 発芽玄米(はつがげんまい), hatsuga-genmai) is unpolished brown rice that has been allowed to germinate to improve the flavor and texture, and to increase lev ...
(GBR), activates enzymes and enhances amino acids including
gamma-aminobutyric acid to improve the nutritional value of brown rice. This method is a result of research carried out for the United Nations
International Year of Rice
The year 2004 was declared the International Year of Rice by the United Nations, noting that rice is a staple food for more than half the world's population, and affirming the need to heighten awareness of the role of rice in alleviating poverty ...
.
![Tteumul](https://upload.wikimedia.org/wikipedia/commons/4/49/Tteumul.jpg)
Rice is cooked by
boiling
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. Th ...
or
steaming
Steaming is a method of cooking using steam. This is often done with a food steamer, a kitchen appliance made specifically to cook food with steam, but food can also be steamed in a wok. In the American southwest, steam pits used for cooking ha ...
, and absorbs water during cooking. With the absorption method, rice may be cooked in a volume of water equal to the volume of dry rice plus any evaporation losses. With the rapid-boil method, rice may be cooked in a large quantity of water which is drained before serving. Rapid-boil preparation is not desirable with enriched rice, as much of the enrichment additives are lost when the water is discarded. Electric
rice cooker
A rice cooker or rice steamer is an automated kitchen appliance designed to boil or steam rice. It consists of a heat source, a cooking bowl, and a thermostat. The thermostat measures the temperature of the cooking bowl and controls the heat. ...
s, popular in Asia and Latin America, simplify the process of cooking rice. Rice (or any other grain) is sometimes quickly fried in oil or fat before boiling (for example
saffron rice or
risotto); this makes the cooked rice less sticky, and is a cooking style commonly called
pilaf
Pilaf ( US spelling) or pilau ( UK spelling) is a rice dish, or in some regions, a wheat dish, whose recipe usually involves cooking in stock or broth, adding spices, and other ingredients such as vegetables or meat, and employing some techniq ...
in
Iran and
Afghanistan or
biryani in
India and
Pakistan.
Dishes
In
Arab cuisine, rice is an ingredient of many soups and dishes with fish, poultry, and other types of meat. It is used to stuff vegetables or is wrapped in grape leaves (
dolma
Dolma (Turkish for “stuffed”) is a family of stuffed dishes associated with Ottoman cuisine, and common in modern national cuisines of regions and countries that once were part of the Ottoman Empire. Some types of dolma are made with whol ...
). When combined with milk, sugar, and honey, it is used to make desserts. In some regions, such as
Tabaristan, bread is made using rice flour. Rice may be made into
congee
Congee or conjee ( ) is a type of rice porridge or gruel eaten in Asian countries. It can be eaten plain, where it is typically served with side dishes, or it can be served with ingredients such as meat, fish, seasonings and flavourings, most o ...
(also called rice porridge or
rice gruel
Congee or conjee ( ) is a type of rice porridge or gruel eaten in Asian countries. It can be eaten plain, where it is typically served with side dishes, or it can be served with ingredients such as meat, fish, seasonings and flavourings, most o ...
) by adding more water than usual, so that the cooked rice is saturated with water, usually to the point that it disintegrates. Rice porridge is commonly eaten as a breakfast food, and is a traditional food for the sick.
Nutrition
Rice is the
staple food
A staple food, food staple, or simply a staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for a given person or group of people, supplying a large fraction of energy needs and ...
of over half the world's population. It is the predominant dietary energy source for 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa. Rice provides 20% of the world's dietary energy supply, while wheat supplies 19% and maize (corn) 5%.
Cooked unenriched long-grain white rice is composed of 68% water, 28%
carbohydrates
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
, 3%
protein, and 1%
fat (table). A reference serving of it provides of
food energy and contains no
micronutrient
Micronutrients are nutrient, essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for exam ...
s in significant amounts, with all less than 10% of the
Daily Value (DV) (table). Cooked short-grain white rice provides the same food energy and contains moderate amounts of
B vitamins,
iron, and
manganese (10–17% DV) per 100-gram serving (table).
A detailed analysis of nutrient content of rice suggests that the nutrition value of rice varies based on a number of factors. It depends on the strain of rice, such as
white,
brown,
red, and
black (or purple) varieties having different prevalence across world regions.
It also depends on nutrient quality of the soil rice is grown in, whether and how the rice is polished or processed, the manner it is enriched, and how it is prepared before consumption.
A 2018
World Health Organization (WHO) guideline showed that
fortification of rice to reduce
malnutrition may involve different micronutrient strategies, including
iron only, iron with
zinc,
vitamin A, and
folic acid, or iron with other
B-complex vitamins
B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexist ...
, such as
thiamin,
niacin
Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...
,
vitamin B6, and
pantothenic acid.
[ A ]systematic review
A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
of clinical research on the efficacy of rice fortification showed the strategy had the main effect of reducing the risk of iron deficiency by 35% and increasing blood levels of hemoglobin.[ The guideline established a major recommendation: "Fortification of rice with iron is recommended as a public health strategy to improve the iron status of populations, in settings where rice is a staple food."][
Rice grown experimentally under elevated carbon dioxide levels, similar to those predicted for the year 2100 as a result of human activity, had less iron, zinc, and protein, as well as lower levels of thiamin, ]riboflavin
Riboflavin, also known as vitamin B2, is a vitamin found in food and sold as a dietary supplement. It is essential to the formation of two major coenzymes, flavin mononucleotide and flavin adenine dinucleotide. These coenzymes are involved in ...
, folic acid, and pantothenic acid.
The following table shows the nutrient content of rice and other major staple foods in a raw form on a dry weight basis to account for their different water contents.
Arsenic concerns
As arsenic occurs in soil, water, and air, the United States Food and Drug Administration (FDA) monitors the levels of arsenic in foods, particularly in rice products used commonly for infant food. While growing, rice plants tend to absorb arsenic more readily than other food crops, requiring expanded testing by the FDA for possible arsenic-related risks associated with rice consumption in the United States.[ In April 2016, the FDA proposed a limit of 100 parts per billion (ppb) for inorganic arsenic in infant ]rice cereal
Rice cereal is the name commonly given to industrially manufactured baby food based on rice. It is also commonly used in Rice Krispy treats. Its ingredient list is not well defined and depends on the manufacturer. It has been recommended by pedi ...
and other foods to minimize exposure of infants to arsenic.[ For water contamination by arsenic, the United States ]Environmental Protection Agency
A biophysical environment is a biotic and abiotic surrounding of an organism or population, and consequently includes the factors that have an influence in their survival, development, and evolution. A biophysical environment can vary in scale f ...
has set a lower standard of 10 ppb.
Arsenic is a Group 1 carcinogen
A group is a number of persons or things that are located, gathered, or classed together.
Groups of people
* Cultural group, a group whose members share the same cultural identity
* Ethnic group, a group whose members share the same ethnic id ...
. The amount of arsenic in rice varies widely with the greatest concentration in brown rice and rice grown on land formerly used to grow cotton, such as in Arkansas, Louisiana, Missouri, and Texas. White rice grown in Arkansas, Louisiana, Missouri, and Texas, which account collectively for 76 percent of American-produced rice, had higher levels of arsenic than other regions of the world studied, possibly because of past use of arsenic-based pesticides to control cotton weevils. Jasmine rice from Thailand and Basmati rice from Pakistan and India contain the least arsenic among rice varieties in one study. China has set a limit of 150 ppb for arsenic in rice.
''Bacillus cereus''
Cooked rice can contain '' Bacillus cereus'' spores, which produce an emetic toxin when left at . When storing cooked rice for use the next day, rapid cooling is advised to reduce the risk of toxin production. One of the enterotoxin
An enterotoxin is a protein exotoxin released by a microorganism that targets the intestines.
Enterotoxins are chromosomally encoded or plasmid encoded exotoxins that are produced and secreted from several bacterial organisms. They are heat labi ...
s produced by ''Bacillus cereus'' is heat-resistant; reheating contaminated rice kills the bacteria, but does not destroy the toxin already present.
Rice-growing environments
Rice growth and production are affected by: the environment, soil properties, biotic conditions, and cultural practices. Environmental factors include rainfall and water, temperature, photoperiod, solar radiation and, in some instances, tropical storms. Soil factors refer to soil type and their position in uplands or lowlands. Biotic factors deal with weeds, insects, diseases, and crop varieties.
Rice can be grown in different environments, depending upon water availability. Generally, rice does not thrive in a waterlogged area, yet it can survive and grow herein and it can survive flooding.
# Lowland, rainfed, which is drought prone, favors medium depth; waterlogged, submergence, and flood prone
# Lowland, irrigated, grown in both the wet season and the dry season
# Deep water or floating rice
# Coastal wetland
# Upland rice (also known as hill rice or Ghaiya rice) is well known for its drought tolerance
History of cultivation
Production and commerce
Production
In 2020, world production of paddy rice was s, led by China and India with a combined 52% of this total.[ Other major producers were Bangladesh, Indonesia and Vietnam. The five major producers accounted for 72% of total production, while the top fifteen producers accounted for 91% of total world production in 2017 (see table on right). Developing countries account for 95% of the total production.][
]
Rice is a major food staple and a mainstay for the rural population and their food security. It is mainly cultivated by small farmers in holdings of less than one hectare. Rice is also a wage commodity for workers in the cash crop or non-agricultural sectors. Rice is vital for the nutrition of much of the population in Asia, as well as in Latin America and the Caribbean and in Africa; it is central to the food security of over half the world population.
Many rice grain producing countries have significant losses post-harvest at the farm and because of poor roads, inadequate storage technologies, inefficient supply chains and farmer's inability to bring the produce into retail markets dominated by small shopkeepers. A World Bank – FAO study claims 8% to 26% of rice is lost in developing nations, on average, every year, because of post-harvest problems and poor infrastructure. Some sources claim the post-harvest losses exceed 40%. Not only do these losses reduce food security in the world, the study claims that farmers in developing countries such as China, India and others lose approximately US$89 billion of income in preventable post-harvest farm losses, poor transport, the lack of proper storage and retail. One study claims that if these post-harvest grain losses could be eliminated with better infrastructure and retail network, in India alone enough food would be saved every year to feed 70 to 100 million people.
Processing
The seeds of the rice plant are first milled using a rice huller to remove the chaff
Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grains or similar fine, dry, scaly plant material (such as scaly parts of flowers or finely chopped straw). Chaff is indigestible by humans, but livestock can eat it. In agri ...
(the outer husks of the grain) (see: rice hulls). At this point in the process, the product is called brown rice. The milling may be continued, removing the bran, ''i.e.'', the rest of the husk and the germ, thereby creating white rice. White rice, which keeps longer, lacks some important nutrients; moreover, in a limited diet which does not supplement the rice, brown rice helps to prevent the disease beriberi.
Either by hand or in a rice polisher, white rice may be buffed with glucose or talc powder (often called polished rice, though this term may also refer to white rice in general), parboiled, or processed into flour. White rice may also be enriched by adding nutrients, especially those lost during the milling process. While the cheapest method of enriching involves adding a powdered blend of nutrients that will easily wash off (in the United States, rice which has been so treated requires a label warning against rinsing), more sophisticated methods apply nutrients directly to the grain, coating the grain with a water-insoluble substance which is resistant to washing.
In some countries, a popular form, parboiled rice (also known as converted rice and easy-cook rice) is subjected to a steaming or parboiling process while still a brown rice grain. The parboil process causes a gelatinisation of the starch in the grains. The grains become less brittle, and the color of the milled grain changes from white to yellow. The rice is then dried, and can then be milled as usual or used as brown rice. Milled parboiled rice is nutritionally superior to standard milled rice, because the process causes nutrients from the outer husk (especially thiamine) to move into the endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...
, so that less is subsequently lost when the husk is polished off during milling. Parboiled rice has an additional benefit in that it does not stick to the pan during cooking, as happens when cooking regular white rice. This type of rice is eaten in parts of India and countries of West Africa are also accustomed to consuming parboiled rice.
Rice bran, called ''nuka'' in Japan, is a valuable commodity in Asia and is used for many daily needs. It is a moist, oily inner layer which is heated to produce oil. It is also used as a pickling bed in making rice bran pickles and '' takuan''.
Raw rice may be ground into flour for many uses, including making many kinds of beverages, such as '' amazake, horchata'', rice milk, and rice wine
Rice wine is an alcoholic beverage fermented and distilled from rice, traditionally consumed in East Asia, Southeast Asia and South Asia. Rice wine is made by the fermentation of rice starch that has been converted to sugars. Microbes are the so ...
. Rice does not contain gluten, so is suitable for people on a gluten-free diet. Rice can be made into various types of noodles. Raw, wild, or brown rice may also be consumed by raw-foodist or fruitarians
Fruitarianism () is a diet related to veganism that consists primarily of consuming fruits and possibly nuts and seeds, but without any animal products. Fruitarian diets are subject to criticism and health concerns.
Fruitarianism may be adopted f ...
if soaked and sprouted (usually a week to 30 days – gaba rice).
Processed rice seeds must be boiled or steamed before eating. Boiled rice may be further fried in cooking oil
Cooking oil is plant, animal, or synthetic liquid fat used in frying, baking, and other types of cooking. It is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips, and may be called edible oil. ...
or butter (known as fried rice), or beaten in a tub to make '' mochi''.
Rice is a good source of protein and a staple food in many parts of the world, but it is not a complete protein
A complete protein or whole protein is a food source of protein that contains an adequate proportion of each of the nine essential amino acids necessary in the human diet.
Amino acid profile
The following table lists the optimal profile of the ...
: it does not contain all of the essential amino acids
An essential amino acid, or indispensable amino acid, is an amino acid that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life form ...
in sufficient amounts for good health, and should be combined with other sources of protein, such as nuts, seeds, beans, fish, or meat.
Rice, like other cereal grains, can be puffed (or popped). This process takes advantage of the grains' water content and typically involves heating grains in a special chamber. Further puffing is sometimes accomplished by processing puffed pellets in a low- pressure chamber. The ideal gas law means either lowering the local pressure or raising the water temperature results in an increase in volume prior to water evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
, resulting in a puffy texture. Bulk raw rice density is about 0.9 g/cm3. It decreases to less than one-tenth that when puffed.
Harvesting, drying and milling
Unmilled rice, known as "paddy" (Indonesia and Malaysia: padi; Philippines, palay), is usually harvested when the grains have a moisture content of around 25%. In most Asian countries, where rice is almost entirely the product of smallholder agriculture, harvesting is carried out manually, although there is a growing interest in mechanical harvesting. Harvesting can be carried out by the farmers themselves, but is also frequently done by seasonal labor groups. Harvesting is followed by threshing, either immediately or within a day or two. Again, much threshing is still carried out by hand but there is an increasing use of mechanical threshers. Subsequently, paddy needs to be dried to bring down the moisture content to no more than 20% for milling.
A familiar sight in several Asian countries is paddy laid out to dry along roads. However, in most countries the bulk of drying of marketed paddy takes place in mills, with village-level drying being used for paddy to be consumed by farm families. Mills either sun dry or use mechanical driers or both. Drying has to be carried out quickly to avoid the formation of molds. Mills range from simple hullers, with a throughput of a couple of tonnes a day, that simply remove the outer husk, to enormous operations that can process a day and produce highly polished rice. A good mill can achieve a paddy-to-rice conversion rate of up to 72% but smaller, inefficient mills often struggle to achieve 60%. These smaller mills often do not buy paddy and sell rice but only service farmers who want to mill their paddy for their own consumption.
Distribution
Because of the importance of rice to human nutrition and food security in Asia, the domestic rice markets tend to be subject to considerable state involvement. While the private sector plays a leading role in most countries, agencies such as BULOG in Indonesia, the NFA in the Philippines, VINAFOOD in Vietnam and the Food Corporation of India are all heavily involved in purchasing of paddy from farmers or rice from mills and in distributing rice to poorer people. BULOG and NFA monopolise rice imports into their countries while VINAFOOD controls all exports from Vietnam.
Trade
World trade figures are very different from those for production, as less than 8% of rice produced is traded internationally. In economic terms, the global rice trade was a small fraction of 1% of world mercantile trade. Many countries consider rice as a strategic food staple, and various governments subject its trade to a wide range of controls and interventions.
Developing countries are the main players in the world rice trade, accounting for 83% of exports and 85% of imports. While there are numerous importers of rice, the exporters of rice are limited. Just five countries—Thailand, Vietnam, China, the United States and India—in decreasing order of exported quantities, accounted for about three-quarters of world rice exports in 2002.[ However, this ranking has been rapidly changing in recent years. In 2010, the three largest exporters of rice, in decreasing order of quantity exported were Thailand, Vietnam and India. By 2012, India became the largest exporter of rice with a 100% increase in its exports on year-to-year basis, and Thailand slipped to third position. Together, Thailand, Vietnam and India accounted for nearly 70% of the world rice exports.
The primary variety exported by Thailand and Vietnam were Jasmine rice, while exports from India included aromatic Basmati variety. China, an exporter of rice in early 2000s, was a net importer of rice in 2010 and will become the largest net importer, surpassing Nigeria, in 2013.][ According to a USDA report, the world's largest exporters of rice in 2012 were India (), Vietnam (), Thailand (), Pakistan () and the United States ().
Major importers usually include Nigeria, Indonesia, Bangladesh, Saudi Arabia, Iran, Iraq, Malaysia, the Philippines, Brazil and some African and Persian Gulf countries. In common with other West African countries, Nigeria is actively promoting domestic production. However, its very heavy import duties (110%) open it to smuggling from neighboring countries. Parboiled rice is particularly popular in Nigeria. Although China and India are the two largest producers of rice in the world, both countries consume the majority of the rice produced domestically, leaving little to be traded internationally.
]
Yield records
The average world yield for rice was , in 2010. Australian rice farms were the most productive in 2010, with a nationwide average of .
Yuan Longping
Yuan Longping (; September 7, 1930May 22, 2021) was a Chinese agronomist and member of the Chinese Academy of Engineering known for developing the first hybrid rice varieties in the 1970s, part of the Green Revolution in agriculture. For his ...
of China National Hybrid Rice Research and Development Center set a world record for rice yield in 2010 at on a demonstration plot. In 2011, this record was reportedly surpassed by an Indian farmer, Sumant Kumar, with in Bihar, although this claim has been disputed by both Yuan and India's Central Rice Research Institute
The National Rice Research Institute has been established since 1966 under Indian Council of Agricultural Research (ICAR) but it was setup on April 23, 1946 at Bidhyadharpur, Cuttack, Odisha with an experimental farm land of 60 hectares.
Researc ...
. These efforts employed newly developed rice breeds and System of Rice Intensification (SRI), a recent innovation in rice farming.
Price
In late 2007 to May 2008, the price of grains rose greatly due to droughts in major producing countries (particularly Australia), increased use of grains for animal feed and US subsidies for bio-fuel production. Although there was no shortage of rice on world markets this general upward trend in grain prices led to panic buying by consumers, government rice export bans (in particular, by Vietnam and India) and inflated import orders by the Philippines marketing board, the National Food Authority. This caused significant rises in rice prices. In late April 2008, prices hit 24 US cents a pound
Pound or Pounds may refer to:
Units
* Pound (currency), a unit of currency
* Pound sterling, the official currency of the United Kingdom
* Pound (mass), a unit of mass
* Pound (force), a unit of force
* Rail pound, in rail profile
Symbols
* Po ...
, twice the price of seven months earlier. Over the period of 2007 to 2013, the Chinese government has substantially increased the price it pays domestic farmers for their rice, rising to per metric ton by 2013.[ The 2013 price of rice originating from other southeast Asian countries was a comparably low per metric ton.][
On April 30, 2008, Thailand announced plans for the creation of the ]Organisation of Rice Exporting Countries
The Organisation of Rice Exporting Countries (OREC) describes a project of a small group of South-East Asian countries to create a homonymous organisation. The group is made up, in alphabetical order, of Cambodia, Laos, Myanmar, Thailand and Viet ...
(OREC) with the intention that this should develop into a price-fixing cartel for rice. However, little progress had been made to achieve this.
Worldwide consumption
, world food consumption of rice was of paddy equivalent ( of milled equivalent), while the largest consumers were China consuming of paddy equivalent (28.7% of world consumption) and India consuming of paddy equivalent (23.1% of world consumption).[
Between 1961 and 2002, per capita consumption of rice increased by 40% worldwide. A paper from the Korean Society of Crop Science anticipated that consumption would increase to 590 million tons by 2040, and that consumption would decline in Asia and increase in other parts of the world.
Rice is the most important crop in Asia. In Cambodia, for example, 90% of the total agricultural area is used for rice production. Per capita, Bangladesh ranks as the country with the highest rice consumption, followed by ]Laos
Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...
, Cambodia, Vietnam and Indonesia.
U.S. rice consumption has risen sharply over the past 25 years, fueled in part by commercial applications such as beer production. Almost one in five adult Americans now report eating at least half a serving of white or brown rice per day.
Environmental impacts
Climate change
The worldwide production of rice accounts for more greenhouse gas emissions (GHG) in total than that of any other plant food. It was estimated in 2021 to be responsible for 30% of agricultural methane emissions and 11% of agricultural nitrous oxide emissions. Methane release is caused by long-term flooding of rice fields, inhibiting the soil from absorbing atmospheric oxygen, a process causing anaerobic fermentation of organic matter in the soil. A 2021 study estimated that rice contributed 2 billion tonnes of anthropogenic greenhouse gases in 2010, of the 47 billion total. The study added up GHG emissions from the entire lifecycle, including production, transportation, and consumption, and compared the global totals of different foods. The total for rice was half the total for beef.
A 2010 study found that, as a result of rising temperatures and decreasing solar radiation during the later years of the 20th century, the rice yield growth rate has decreased in many parts of Asia, compared to what would have been observed had the temperature and solar radiation trends not occurred. The yield growth rate had fallen 10–20% at some locations. The study was based on records from 227 farms in Thailand, Vietnam, Nepal, India, China, Bangladesh, and Pakistan. The mechanism of this falling yield was not clear, but might involve increased respiration during warm nights, which expends energy without being able to photosynthesize. More detailed analysis of rice yields by the International Rice Research Institute forecast 20% reduction in yields in Asia per degree Celsius of temperature rise. Rice becomes sterile if exposed to temperatures above 35 degrees for more than one hour during flowering and consequently produces no grain.
Water usage
Rice requires slightly more water to produce than other grains. Rice production uses almost a third of Earth's fresh water. Water outflows from rice fields through transpiration, evaporation
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
, seepage, and percolation. It is estimated that it takes about of water need to be supplied to account for all of these outflows and produce of rice.
Pests and diseases
Rice pests are any organisms or microbe
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s with the potential to reduce the yield or value of the rice crop (or of rice seeds). Rice pests include weeds, pathogens, insects, nematode, rodents, and birds. A variety of factors can contribute to pest outbreaks, including climatic factors, improper irrigation, the overuse of insecticides and high rates of nitrogen fertilizer application. Weather conditions also contribute to pest outbreaks. For example, rice gall midge and army worm outbreaks tend to follow periods of high rainfall early in the wet season, while thrips outbreaks are associated with drought.
Animal pests
Insects
Major rice insect pests include: the brown planthopper
The brown planthopper (BPH), ''Nilaparvata lugens'' (Stål) (Hemiptera: Delphacidae) is a planthopper species that feeds on rice plants (''Oryza sativa'' L.). These insects are among the most important pests of rice, which is the major staple cro ...
(BPH), several species of stemborer A stemborer (stem borer) is any insect larva, or arthropod, that bores into plant stems. However the term most frequently refers among the Coleoptera to the larva of certain longhorn beetles such as '' Dorysthenes buqueti'' and those of the genus '' ...
s—including those in the genera '' Scirpophaga'' and '' Chilo'', the rice gall midge, several species of rice bugs,[ notably in the genus '']Leptocorisa
''Leptocorisa''Latreille PA (1829) ''Le règne animal distribué d'après son organisation, pour servir de base à l'histoire naturelle des animaux et d'introduction à l'anatomie comparée. Déterville, Paris.'' Vol. t.5 (1829): i-xxiv; 1-556. i ...
'', defoliators such as the rice: leafroller
The Tortricidae are a family of moths, commonly known as tortrix moths or leafroller moths, in the order Lepidoptera. This large family has over 11,000 species described, and is the sole member of the superfamily Tortricoidea, although the genus ...
, hispa and grasshoppers. The fall army worm, a species of Lepidoptera, also targets and causes damage to rice crops. Rice weevil
Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera ''Zizania'' and '' Porteresia'', both wild and domesticated, ...
s attack stored produce.
Nematodes
Several nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
species infect rice crops, causing diseases such as Ufra ('' Ditylenchus dipsaci''), White tip disease ('' Aphelenchoide bessei''), and root knot disease (''Meloidogyne graminicola
Root-knot nematodes are plant-parasitic nematodes from the genus ''Meloidogyne''. They exist in soil in areas with hot climates or short winters. About 2000 plants worldwide are susceptible to infection by root-knot nematodes and they cause appro ...
''). Some nematode species such as '' Pratylenchus'' spp. are most dangerous in upland rice of all parts of the world. Rice root nematode (''Hirschmanniella oryzae
''Hirschmanniella oryzae'', i.e. rice root nematode (RRN), is among the major pests of rice and is the most common plant-parasitic nematode found on irrigated rice. Recent modifications in cultivation practices have led to a substantial increas ...
'') is a migratory endoparasite which on higher inoculum levels will lead to complete destruction of a rice crop. Beyond being obligate parasites, they also decrease the vigor of plants and increase the plants' susceptibility to other pests and diseases.
Other pests
These include the apple snail ('' Pomacea canaliculata''), panicle rice mite
''Steneotarsonemus spinki'', the panicle rice mite, spinki mite, or rice tarsonemid mite, is a species of mite in the family Tarsonemidae, the white mites. It is a serious pest of rice in tropical Asia, Central America, and the Caribbean.
Id ...
, rat
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include ''Neotoma'' ( pack rats), ''Bandicota'' (bandicoot ...
s, and the weed '' Echinochloa crusgali''.
Diseases
Rice blast, caused by the fungus ''Magnaporthe grisea
''Magnaporthe grisea'', also known as rice blast fungus, rice rotten neck, rice seedling blight, blast of rice, oval leaf spot of graminea, pitting disease, ryegrass blast, Johnson spot, neck blast, wheat blast, and Imochi (Japanese:稲熱) is a ...
'' (syn.
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently.
* In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...
''M. oryzae'', ''Pyricularia oryzae''), is the most significant disease affecting rice cultivation. It and bacterial leaf streak
Bacterial leaf streak (BLS), also known as black chaff, is a common bacterial disease of wheat. The disease is caused by the bacterial species '' Xanthomonas translucens'' pv. ''undulosa''. The pathogen is found globally, but is a primary problem ...
(caused by ''Xanthomonas oryzae'' pv. ''oryzae'') are perennially the two worst rice diseases worldwide, and such is their importance and the importance of rice that they are both among the worst 10 diseases of all plants.[p.214, "Rice blast (caused by the fungal pathogen ''Magnaporthe oryzae'') and bacterial blight (caused by the bacterial pathogen ''Xanthomonas oryzae'' pv. ''oryzae'') are the most devastating rice diseases (119) and are among the 10 most important fungal and bacterial diseases in plants (32, 95). Owing to their scientific and economic importance, both pathosystems have been the focus of concentrated study over the past two decades, and they are now advanced molecular models for plant fungal and bacterial diseases."] Fukuoka ''et al.'', 2009 clones one of the few quantitative disease loci
Quantitative may refer to:
* Quantitative research, scientific investigation of quantitative properties
* Quantitative analysis (disambiguation)
* Meter (poetry), Quantitative verse, a metrical system in poetry
* Statistics, also known as quantit ...
for quantitative disease resistance
Quantitative may refer to:
* Quantitative research, scientific investigation of quantitative properties
* Quantitative analysis (disambiguation)
* Meter (poetry), Quantitative verse, a metrical system in poetry
* Statistics, also known as quantit ...
ever cloned in plants, one for blast resistance in this crop.[
] The plant responds to the blast pathogen by releasing jasmonic acid
Jasmonic acid (JA) is an organic compound found in several plants including jasmine. The molecule is a member of the jasmonate class of plant hormones. It is biosynthesized from linolenic acid by the octadecanoid pathway. It was first isolat ...
, which then cascades into the activation of further downstream metabolic pathways which produce the defense response. This accumulates as methyl-jasmonic acid. The pathogen responds by synthesizing an oxidizing enzyme which prevents this accumlation and its resulting alarm signal.[
]
Other major fungal and bacterial rice diseases include sheath blight
Rice-sheath blight is a disease caused by ''Rhizoctonia solani'' (teleomorph is '' Thanetophorus cucumeris''), a basidiomycete, that causes major limitations on rice production in India and other countries of Asia. It is also a problem in the sout ...
(caused by ''Rhizoctonia solani
''Rhizoctonia solani'' is a species of fungus in the order Cantharellales. Basidiocarps (fruit bodies) are thin, effused, and web-like, but the fungus is more typically encountered in its anamorphic state, as hyphae and sclerotia. The name ''Rhi ...
''), false smut (''Ustilaginoidea virens
''Ustilaginoidea virens'', perfect sexual stage '' Villosiclava virens'',Tanaka, Eiji, Taketo Ashizawa, Ryoichi Sonoda & Chihiro Tanaka. Villosiclava virens gen. nov., comb. nov., teleomorph of Ustilaginoidea virens, the causal agent of rice fal ...
''), bacterial panicle blight (''Burkholderia glumae
''Burkholderia glumae'' is a Gram-negative soil bacterium
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorgani ...
''),[p.214, "...other diseases, including rice sheath blight (caused by the fungal pathogen ''Rhizoctonia solani''), false smut (caused by the fungal pathogen ''Ustilaginoidea virens''), bacterial leaf streak (caused by ''X. oryzae'' pv. ''oryzicola''), bacterial panicle blight (''Burkholderia glumae''), are emerging globally as important rice diseases (53, 72, 180) (Figure 1)."] sheath rot (''Sarocladium oryzae
''Sarocladium oryzae'' (Sawada) is a plant pathogen causing the sheath rot disease of rice and bamboo blight in Asia.
Taxonomy and morphology
''Sarocladium oryzae'' has irregularly penicillate conidiophores and slimy, 1-celled conidia.
''Sa ...
''), and ''bakanae
or bakanae disease (, , ), from the Japanese for "foolish seedling", is a disease that infects the rice plant. It is caused by the fungus ''Gibberella fujikuroi'', the metabolism of which produces a surplus of gibberellic acid. In the plant, this ...
'' ('' Fusarium fujikuroi'').[p.214, Table 1: Important fungal and bacterial diseases in rice.] Viral diseases exist, such as rice ragged stunt ( vector: BPH), and tungro
This article is a list of diseases of rice (''Oryza sativa''). Diseases have historically been one of the major causes of rice shortages. p.434
Bacterial diseases
Fungal diseases
Viruses
*'' Rice black-streaked dwarf virus''
*'' Rice bunch ...
(vector: ''Nephotettix
''Nephotettix'' is a genus of planthoppers in the subfamily Deltocephalinae and tribe Chiasmini. Species are mostly found in Asia, although two are from Africa.
Known as 'green leafhoppers' of paddy/rice, ''Nephotettix cincticeps'' and ''N. vi ...
'' spp). Many viral diseases, especially those vectored by planthopper
A planthopper is any insect in the infraorder Fulgoromorpha, in the suborder Auchenorrhyncha, a group exceeding 12,500 described species worldwide. The name comes from their remarkable resemblance to leaves and other plants of their environment ...
s and leafhopper
A leafhopper is the common name for any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and a ...
s, are major causes of losses across the world. There is also an ascomycete
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...
fungus, ''Cochliobolus miyabeanus
''Cochliobolus miyabeanus'' (formerly known as ''Helminthosporium oryzae'') is a fungus that causes brown spot disease in rice.
It was considered for use by the USA as a biological weapon against Japan during World War II.
Hosts and symptoms
...
'', that causes brown spot disease in rice.
Integrated pest management
Crop protection
Crop protection is the science and practice of managing plant diseases, weeds, and other pests (both vertebrate and invertebrate) that damage crops and forestry. Crops include field crops (maize, wheat, rice, etc.), vegetable crops (potatoes, cabb ...
scientists are trying to develop rice pest management techniques which are sustainable
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livin ...
. In other words, to manage crop pests in such a manner that future crop production is not threatened. Sustainable pest management is based on four principles: biodiversity, host plant resistance (HPR), landscape ecology, and hierarchies in a landscape—from biological to social. At present, rice pest management includes cultural techniques, pest-resistant rice varieties, and pesticides
Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampric ...
(which include insecticide
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
). Increasingly, there is evidence that farmers' pesticide applications are often unnecessary, and even facilitate pest outbreaks. By reducing the populations of natural enemies of rice pests, misuse of insecticides can actually lead to pest outbreaks. The International Rice Research Institute (IRRI) demonstrated in 1993 that an 87.5% reduction in pesticide use can lead to an overall drop in pest numbers. IRRI also conducted two campaigns in 1994 and 2003, respectively, which discouraged insecticide misuse and smarter pest management in Vietnam.
Rice plants produce their own chemical defenses to protect themselves from pest attacks. Some synthetic chemicals, such as the herbicide 2,4-D, cause the plant to increase the production of certain defensive chemicals and thereby increase the plant's resistance to some types of pests. Conversely, other chemicals, such as the insecticide imidacloprid, can induce changes in the gene expression of the rice that cause the plant to become more susceptible to attacks by certain types of pests. 5-Alkylresorcinol
Alkylresorcinols, also known as resorcinolic lipids, are phenolic lipids composed of long aliphatic chains and resorcinol-type phenolic rings.
Natural sources of alkylresorcinols
Alkylresorcinols are relatively rare in nature, with the main know ...
s are chemicals that can also be found in rice.
Botanicals, so-called "natural pesticides", are used by some farmers in an attempt to control rice pests. Botanicals include extracts of leaves, or a mulch of the leaves themselves. Some upland rice farmers in Cambodia spread chopped leaves of the bitter bush ('' Chromolaena odorata'') over the surface of fields after planting. This practice probably helps the soil retain moisture and thereby facilitates seed germination. Farmers also claim the leaves are a natural fertilizer and helps suppress weed and insect infestations.
Among rice cultivars, there are differences in the responses to, and recovery from, pest damage. Many rice varieties have been selected for resistance to insect pests. Therefore, particular cultivars are recommended for areas prone to certain pest problems. The genetically based ability of a rice variety to withstand pest attacks is called resistance. Three main types of plant resistance to pests are recognized as nonpreference, antibiosis, and tolerance.[ Nonpreference (or antixenosis) describes host plants which insects prefer to avoid; antibiosis is where insect survival is reduced after the ingestion of host tissue; and tolerance is the capacity of a plant to produce high yield or retain high quality despite insect infestation.
Over time, the use of pest-resistant rice varieties selects for pests that are able to overcome these mechanisms of resistance. When a rice variety is no longer able to resist pest infestations, resistance is said to have broken down. Rice varieties that can be widely grown for many years in the presence of pests and retain their ability to withstand the pests are said to have durable resistance. Mutants of popular rice varieties are regularly screened by plant breeders to discover new sources of durable resistance.]
Parasitic weeds
Rice is parasitized by the eudicot weed ''Striga hermonthica
''Striga hermonthica'', commonly known as purple witchweed or giant witchweed, is a hemiparasitic plant that belongs to the family Orobanchaceae. It is devastating to major crops such as sorghum (''Sorghum bicolor'') and rice (''Oryza sativa'') ...
'', which is of local importance for this crop.
Ecotypes and cultivars
While most rice is bred for crop quality and productivity, there are varieties selected for characteristics such as texture, smell, and firmness. There are four major categories of rice worldwide: indica, japonica, aromatic and glutinous. The different varieties of rice are not considered interchangeable, either in food preparation or agriculture, so as a result, each major variety is a completely separate market from other varieties. It is common for one variety of rice to rise in price while another one drops in price.
Rice cultivars also fall into groups according to environmental conditions, season of planting, and season of harvest, called ecotypes. Some major groups are the Japan-type (grown in Japan), "buly" and "tjereh" types (Indonesia); ''sali'' (or ''aman''—main winter crop), ''ahu'' (also ''aush'' or ''ghariya'', summer), and ''boro'' (spring) (Bengal and Assam). Cultivars exist that are adapted to deep flooding, and these are generally called "floating rice".
The largest collection of rice cultivars is at the International Rice Research Institute in the Philippines, with over 100,000 rice accessions held in the International Rice Genebank. Rice cultivars are often classified by their grain shapes and texture. For example, Thai Jasmine rice is long-grain and relatively less sticky, as some long-grain rice contains less amylopectin than short-grain cultivars. Chinese restaurants often serve long-grain as plain unseasoned steamed rice though short-grain rice is common as well. Japanese mochi rice and Chinese sticky rice are short-grain. Chinese people use sticky rice which is properly known as "glutinous rice" (note: glutinous refer to the glue-like characteristic of rice; does not refer to "gluten") to make zongzi. The Japanese table rice is a sticky, short-grain rice. Japanese sake rice is another kind as well.
Indian rice cultivars include long-grained and aromatic Basmati (ਬਾਸਮਤੀ) (grown in the North), long and medium-grained Patna rice
Patna (
), historically known as Pataliputra, is the List of state and union territory capitals in India, capital and largest city of the state of Bihar in India. According to the United Nations, as of 2018, Patna had a population of 2.35  ...
, and in South India ( Andhra Pradesh and Karnataka) short-grained Sona Masuri (also called as Bangaru theegalu). In the state of Tamil Nadu, the most prized cultivar is ''ponni'' which is primarily grown in the delta regions of the Kaveri River. Kaveri is also referred to as ponni in the South and the name reflects the geographic region where it is grown. In the Western Indian state of Maharashtra
Maharashtra (; , abbr. MH or Maha) is a states and union territories of India, state in the western India, western peninsular region of India occupying a substantial portion of the Deccan Plateau. Maharashtra is the List of states and union te ...
, a short grain variety called Ambemohar Ambemohar is a fragrant rice variant grown in the foothills of the Western ghats region of the state of Maharashtra in India.
History and etymology
The word Ambemohar means mango blossom in the Marathi language, which is spoken in the state of M ...
is very popular. This rice has a characteristic fragrance of Mango blossom.
Aromatic rices have definite aromas and flavors; the most noted cultivars are Thai fragrant rice, Basmati, Patna rice, Vietnamese fragrant rice, and a hybrid
Hybrid may refer to:
Science
* Hybrid (biology), an offspring resulting from cross-breeding
** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species
** Hybridity, the property of a hybrid plant which is a union of two dif ...
cultivar from America, sold under the trade name Texmati. Both Basmati and Texmati have a mild popcorn
Popcorn (also called popped corn, popcorns or pop-corn) is a variety of corn kernel which expands and puffs up when heated; the same names also refer to the foodstuff produced by the expansion.
A popcorn kernel's strong hull contains the se ...
-like aroma and flavor. In Indonesia, there are also ''red'' and ''black'' cultivars.
High-yield cultivars of rice suitable for cultivation in Africa and other dry ecosystems, called the new rice for Africa
New Rice for Africa ("NERICA") is a cultivar group of interspecific hybrid rice developed by the Africa Rice Center (AfricaRice) to improve the yield of African rice cultivars. Although 240 million people in West Africa rely on rice as the primar ...
(NERICA) cultivars, have been developed. It is hoped that their cultivation will improve food security in West Africa.
Draft genomes for the two most common rice cultivars, ''indica'' and ''japonica'', were published in April 2002. Rice was chosen as a model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
for the biology of grasses because of its relatively small genome (~430 megabase pairs
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
). Rice was the first crop with a complete genome sequence.
On December 16, 2002, the UN General Assembly declared the year 2004 the International Year of Rice. The declaration was sponsored by more than 40 countries.
Varietal development
Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce cro ...
has ceremonial and historical significance for some cultures (see below). The Thai kings have patronised rice breeding since at least the reign of Chulalongkorn
Chulalongkorn ( th, จุฬาลงกรณ์, 20 September 1853 – 23 October 1910) was the fifth monarch of Siam under the House of Chakri, titled Rama V. He was known to the Siamese of his time as ''Phra Phuttha Chao Luang'' (พร ...
, and his great-great-grandson Vajiralongkorn
Vajiralongkorn ( th, วชิราลงกรณ; , ; born 28 July 1952) is the King of Thailand. He is the only son of King Bhumibol Adulyadej and Queen Sirikit. In 1972, at the age of 20, he was made crown prince by his father. After his ...
released five particular rice varieties to celebrate his coronation.
Biotechnology
High-yielding varieties
The high-yielding varieties are a group of crops created intentionally during the Green Revolution to increase global food production. This project enabled labor markets in Asia to shift away from agriculture, and into industrial sectors. The first "Rice Car", IR8 was produced in 1966 at the International Rice Research Institute which is based in the Philippines at the University of the Philippines' Los Baños site. IR8 was created through a cross between an Indonesian variety named "Peta" and a Chinese variety named "Dee Geo Woo Gen."[. IRRI Knowledge Bank.]
Scientists have identified and cloned many genes involved in the gibberellin signaling pathway, including GAI1 ( Gibberellin Insensitive) and SLR1 (Slender Rice). Disruption of gibberellin signaling can lead to significantly reduced stem growth leading to a dwarf phenotype. Photosynthetic investment in the stem is reduced dramatically as the shorter plants are inherently more stable mechanically. Assimilates become redirected to grain production, amplifying in particular the effect of chemical fertilizers on commercial yield. In the presence of nitrogen fertilizers, and intensive crop management, these varieties increase their yield two to three times.
Future potential
As the UN Millennium Development project seeks to spread global economic development to Africa, the "Green Revolution" is cited as the model for economic development. With the intent of replicating the successful Asian boom in agronomic productivity, groups like the Earth Institute are doing research on African agricultural systems, hoping to increase productivity. An important way this can happen is the production of " New Rices for Africa" (NERICA). These rices, selected to tolerate the low input and harsh growing conditions of African agriculture, are produced by the African Rice Center, and billed as technology "from Africa, for Africa". The NERICA have appeared in ''The New York Times'' (October 10, 2007) and ''International Herald Tribune'' (October 9, 2007), trumpeted as miracle crops that will dramatically increase rice yield in Africa and enable an economic resurgence. Ongoing research in China to develop perennial rice
Perennial rice are varieties of long-lived rice that are capable of regrowing season after season without reseeding; they are being developed by plant geneticists at several institutions. Although these varieties are genetically distinct and wil ...
could result in enhanced sustainability and food security.
Golden rice
Expression of human proteins
Ventria Bioscience
Ventria Bioscience is a biotech company with a focus on human nutrition and human therapeutics. The company was established in 1993 in Colorado. The company's core technology is a genetically modified crop-based protein production system (also ...
has genetically modified rice to express
Express or EXPRESS may refer to:
Arts, entertainment, and media Films
* '' Express: Aisle to Glory'', a 1998 comedy short film featuring Kal Penn
* '' The Express: The Ernie Davis Story'', a 2008 film starring Dennis Quaid
Music
* ''Express'' ...
lactoferrin, lysozyme which are proteins
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
usually found in breast milk
Breast milk (sometimes spelled as breastmilk) or mother's milk is milk produced by mammary glands located in the breast of a human female. Breast milk is the primary source of nutrition for newborns, containing fat, protein, carbohydrates ( lacto ...
, and human serum albumin, These proteins have antiviral, antibacterial, and antifungal
An antifungal medication, also known as an antimycotic medication, is a pharmaceutical fungicide or fungistatic used to treat and prevent mycosis such as athlete's foot, ringworm, candidiasis (thrush), serious systemic infections such as crypto ...
effects.
Rice containing these added proteins can be used as a component in oral rehydration solutions which are used to treat diarrheal diseases, thereby shortening their duration and reducing recurrence. Such supplements may also help reverse anemia.
Flood-tolerant rice
Due to the varying levels that water can reach in regions of cultivation, flood tolerant varieties have long been developed and used. Flooding is an issue that many rice growers face, especially in South and South East Asia where flooding annually affects . Standard rice varieties cannot withstand stagnant flooding of more than about a week, mainly as it disallows the plant access to necessary requirements such as sunlight and essential gas exchanges, inevitably leading to plants being unable to recover.
In the past, this has led to massive losses in yields, such as in the Philippines, where in 2006, rice crops worth $65 million were lost to flooding.["] Recently developed cultivars seek to improve flood tolerance.
Drought-tolerant rice
Drought represents a significant environmental stress for rice production, with of rainfed rice production in South and South East Asia often at risk.["] Under drought conditions, without sufficient water to afford them the ability to obtain the required levels of nutrients from the soil, conventional commercial rice varieties can be severely affected—for example, yield losses as high as 40% have affected some parts of India, with resulting losses of around US$800 million annually.
The International Rice Research Institute conducts research into developing drought-tolerant rice varieties, including the varieties 5411 and Sookha dhan, currently being employed by farmers in the Philippines and Nepal respectively. In addition, in 2013 the Japanese National Institute for Agrobiological Sciences led a team which successfully inserted the DEEPER ROOTING 1 (DRO1) gene, from the Philippine upland
Upland or Uplands may refer to:
Geography
*Hill, an area of higher land, generally
*Highland, an area of higher land divided into low and high points
*Upland and lowland, conditional descriptions of a plain based on elevation above sea level
*I ...
rice variety Kinandang Patong, into the popular commercial rice variety IR64, giving rise to a far deeper root system in the resulting plants. This facilitates an improved ability for the rice plant to derive its required nutrients in times of drought via accessing deeper layers of soil, a feature demonstrated by trials which saw the IR64 + DRO1 rice yields drop by 10% under moderate drought conditions, compared to 60% for the unmodified IR64 variety.
Salt-tolerant rice
Soil salinity
Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the ...
poses a major threat to rice crop productivity, particularly along low-lying coastal areas during the dry season. For example, roughly of the coastal areas of Bangladesh are affected by saline soils. These high concentrations of salt can severely affect rice plants' normal physiology, especially during early stages of growth, and as such farmers are often forced to abandon these otherwise potentially usable areas.["]
Progress has been made, however, in developing rice varieties capable of tolerating such conditions; the hybrid created from the cross between the commercial rice variety IR56 and the wild rice species ''Oryza coarctata'' is one example.["] ''O. coarctata'' is capable of successful growth in soils with double the limit of salinity of normal varieties, but lacks the ability to produce edible rice. Developed by the International Rice Research Institute, the hybrid
Hybrid may refer to:
Science
* Hybrid (biology), an offspring resulting from cross-breeding
** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species
** Hybridity, the property of a hybrid plant which is a union of two dif ...
variety can utilise specialised leaf glands that allow for the removal of salt into the atmosphere. It was initially produced from one successful embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
out of 34,000 crosses between the two species; this was then backcrossed to IR56 with the aim of preserving the genes responsible for salt tolerance that were inherited from ''O. coarctata''. Extensive trials are planned prior to the new variety being available to farmers by approximately 2017–18.
When the problem of soil salinity
Soil salinity is the salt content in the soil; the process of increasing the salt content is known as salinization. Salts occur naturally within soils and water. Salination can be caused by natural processes such as mineral weathering or by the ...
arises it will be opportune to select salt tolerant varieties (IRRI or to resort to soil salinity control.
Soil salinity is often measured as the electric conductivity (EC) of the extract of a saturated soil paste (ECe). The EC units are usually expressed in decisiemens per metre or dS/m. The critical ECe value of 5.5 dS/m in the figure, obtained from measurements in farmers' fields, indicates that the rice crop is slightly salt sensitive.
Environment-friendly rice
Producing rice in paddies is harmful for the environment due to the release of methane by methanogenic bacteria
Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain Archaea. All known methanogens are members of the archaeal phylum Euryarchaeota. Methanogens are co ...
. These bacteria live in the anaerobic waterlogged soil, and live off nutrients released by rice roots. Researchers have recently reported in ''Nature'' that putting the barley gene SUSIBA2 into rice creates a shift in biomass production from root to shoot (above ground tissue becomes larger, while below ground tissue is reduced), decreasing the methanogen population, and resulting in a reduction of methane emissions of up to 97%. Apart from this environmental benefit, the modification also increases the amount of rice grains by 43%, which makes it a useful tool in feeding a growing world population.
Meiosis and DNA repair
Rice is used as a model organism for investigating the molecular mechanisms of meiosis and DNA repair in higher plants. Meiosis is a key stage of the sexual cycle in which diploid cells in the ovule (female structure) and the anther
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filam ...
(male structure) produce haploid cells that develop further into gametophytes and gametes. So far, 28 meiotic genes of rice have been characterized. Studies of rice gene OsRAD51C showed that this gene is necessary for homologous recombinational repair of DNA, particularly the accurate repair of DNA double-strand breaks during meiosis. Rice gene OsDMC1 was found to be essential for pairing of homologous chromosomes during meiosis, and rice gene OsMRE11 was found to be required for both synapsis of homologous chromosomes and repair of double-strand breaks during meiosis.
Cultural roles of rice
Rice plays an important role in certain religions and popular beliefs. In many cultures relatives will scatter rice during or towards the end of a wedding ceremony in front of the bride and groom.
The pounded rice ritual
The pounded rice ritual normally occurs with an arranged marriage occurring in Southeast Asia.
An arranged marriage is one where elders of the prospective families negotiate the union with varying levels of input and involvement from the brid ...
is conducted during weddings in Nepal. The bride gives a leafplate full of pounded rice to the groom after he requests it politely from her.
In the Philippines rice wine, popularly known as ''tapuy
''Tapuy'', also spelled ''tapuey'' or ''tapey'', is a rice wine produced in the Philippines. It is a traditional beverage originated from Banaue and the Mountain Province, where it is used for important occasions such as weddings, rice harvestin ...
'', is used for important occasions such as weddings, rice harvesting ceremonies and other celebrations.
Dewi Sri is the traditional rice goddess of the Javanese, Sundanese
Sundanese may refer to:
* Sundanese people
* Sundanese language
* Sundanese script
Standard Sundanese script (''Aksara Sunda Baku'', ) is a writing system which is used by the Sundanese people. It is built based on Old Sundanese script (' ...
, and Balinese people
The Balinese people ( id, suku Bali; ban, ᬳᬦᬓ᭄ᬩᬮᬶ, anak Bali) are an Austronesian ethnic group native to the Indonesian island of Bali. The Balinese population of 4.2 million (1.7% of Indonesia's population) live mostly on the ...
in Indonesia. Most rituals involving Dewi Sri are associated with the mythical origin attributed to the rice plant, the staple food of the region. In Thailand, a similar rice deity is known as '' Phosop''; she is a deity more related to ancient local folklore than a goddess of a structured, mainstream religion. The same female rice deity is known as ''Po Ino Nogar'' in Cambodia and as ''Nang Khosop'' in Laos
Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...
. Ritual offerings are made during the different stages of rice production to propitiate the Rice Goddess in the corresponding cultures.
A 2014 study of Han Chinese communities found that a history of farming rice makes cultures more psychologically interdependent, whereas a history of farming wheat makes cultures more independent.
A Royal Ploughing Ceremony is held in certain Asian countries to mark the beginning of the rice planting season. It is still honored in the kingdoms of Cambodia and Thailand. The 2,600-year-old tradition begun by Śuddhodana in Kapilavastu
Kapilavastu may refer to:
*Kapilavastu (ancient city), ancient city, the capital of Shakya
*Taulihawa, Nepal, or Kapilavastu, municipality in Province No. 5, Nepal
*Kapilvastu District
Kapilvastu district ( ne, कपिलवस्तु ज ...
was revived in the republic of Nepal in 2017 after a lapse of a few years.
Thai king Vajiralongkorn
Vajiralongkorn ( th, วชิราลงกรณ; , ; born 28 July 1952) is the King of Thailand. He is the only son of King Bhumibol Adulyadej and Queen Sirikit. In 1972, at the age of 20, he was made crown prince by his father. After his ...
released five particular rice varieties to celebrate his coronation.
See also
* Artificial rice
Artificial rice is a grain product made to resemble rice. It is usually made from broken rice, sometimes with the addition of other cereals, and often fortified with micronutrients, including minerals such as iron and zinc and vitamins, such as v ...
* Glutinous rice
Glutinous rice (''Oryza sativa var. glutinosa''; also called sticky rice, sweet rice or waxy rice) is a type of rice grown mainly in Southeast and East Asia, and the northeastern regions of South Asia, which has opaque grains, very low amylose ...
* List of dried foods
* List of rice cultivars
* List of rice dishes This is a list of rice dishes from all over the world, arranged alphabetically. 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 widely consumed staple fo ...
* Maratelli
Maratelli is a ''semifino'' rice native to the Asigliano Vercellese province of Vercelli in northern Italy. It is a stable rice genotype that maintains its features. In 1970 it covered 8% of Italian rice-cultivated fields. Maratelli rice keeps i ...
rice
* Mushroom production on rice straw
* Leaf Color Chart
The Leaf Color Chart (LCC) is a diagnostic tool used to determine the nitrogen level in rice plants relative to the shade of green of the plant's leaves. It is a ruler-shaped strip containing at least four panels of color, ranging from yellowish ...
* Post-harvest losses
* Puffed rice
* Rice Belt
* Rice bran oil
* Rice bread
Rice bread is a type of bread that is made from rice flour rather than wheat flour. Being gluten free, it will not cause adverse reactions for people with gluten intolerance.
The Vietnamese banh mi (baguette) is traditionally made with a mixtur ...
* Rice wine
Rice wine is an alcoholic beverage fermented and distilled from rice, traditionally consumed in East Asia, Southeast Asia and South Asia. Rice wine is made by the fermentation of rice starch that has been converted to sugars. Microbes are the so ...
* Rice writing
Rice writing is the art and skill of being able to write small enough to write on a grain of rice.
History
Rice writing originated in ancient Anatolia in Turkey and India. Many rituals and rites use rice as a medium, but at some point in ancient ...
* Rijsttafel
( , ), a Dutch word that literally translates to "rice table", is an Indonesian elaborate meal adapted by the Dutch following the ''hidang'' presentation of ''nasi padang'' from the Padang region of West Sumatra. It consists of many (forty is ...
* Risotto
* Straw
Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number ...
* System of Rice Intensification
* Texas rice production
* Upland rice
* Wild rice
Notes
References
Further reading
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External links
International Rice Research Institute
{{Authority control
Crops originating from China
Grasses of Asia
Plant models
Types of food
Tropical agriculture