Rice: Edible Starchy Cereal Grain (Thoroughly Explained)

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, although the term may also be used for primitive or uncultivated varieties of Oryza.

Scientific Classification

  • Kingdom: Plantae
  • Clade: Tracheophytes
  • Clade: Angiosperms
  • Clade: Monocots
  • Clade: Commelinids
  • Order: Poales
  • Family: Poaceae
  • Genus: Oryza
  • Species: O. sativa

Rice, an annual grass belongs to the genus Oryza. There are about twenty-three species out of which only two species have been known of their commercial value being used for cultivation. These two species are Oryza sativa (Asian rice) and Oryza glaberrima (African rice). The Oryza sativa is the most commonly grown species throughout the world today while Oryza glaberrima is grown only in South Africa.

In Asia, Oryza sativa is differentiated into three sub-species based on geographical conditions, viz., indica, japonica, and javanica. The variety indica refers to the tropical and sub-tropical varieties grown throughout South and South-East Asia and Southern China.

As a cereal grain, domesticated rice is the most widely consumed staple food for over half of the world’s human population, especially in Asia and Africa. It is the agricultural commodity with the third-highest worldwide production (rice, 741.5 million metric tons or 817.4 million short tons in 2014), after sugarcane (1.9 billion metric tons or 2.1 billion short tons) and maize (1.0 billion metric tons or 1.1 billion short tons).

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. Rice is:

  • Self-pollinated crop
  • Semi-aquatic plant

Rice Edible Starchy Grain

Rice, (Oryza sativa), edible starchy cereal grain, and the grass plant (family 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; 95 percent of the world’s rice crop is eaten by humans.

Rice is cooked by boiling, or it can be ground into flour. It is eaten alone and in a great variety of soups, side dishes, and main dishes in Asian, Middle Eastern, and many other cuisines. Other products in which rice is used are breakfast cereals, noodles, and such alcoholic beverages as Japanese sake.

Physical Description

The cultivated rice plant is an annual grass and grows to about 1.2 meters (4 feet) in height. The leaves are long and flattened and are borne on hollow stems. The fibrous root system is often broad and spreading. The panicle, or inflorescence (flower cluster), is made up of spikelets bearing flowers that produce the fruit, or grain. Varieties differ greatly in the length, shape, and weight of the panicle and the overall productivity of a given plant.

In the 1960s the so-called Green Revolution, an international scientific effort to diminish the threat of world hunger, produced improved strains of numerous food crops, including that known as miracle rice. Bred for disease resistance and increased productivity, this variety is characterized by a short sturdy stalk that minimizes loss from drooping. Poor soil conditions and other factors, however, inhibited its anticipated widespread success.

Domestication and Cultivation

Many cultures have evidence of early rice cultivation, including China, India, and the civilizations of Southeast Asia. However, the earliest archaeological evidence comes from central and eastern China and dates to 7000–5000 BCE. More than 90 percent of the world’s rice is grown in Asia, principally in China, India, Indonesia, and Bangladesh, with smaller amounts grown in Japan, Pakistan, and various Southeast Asian nations. Rice is also cultivated in parts of Europe, in North and South America, and in Australia.

With the exception of the type called upland rice, the plant is grown on submerged land in the coastal plains, tidal deltas, and river basins of tropical, semitropical, and temperate regions. The seeds are sown in prepared beds, and when the seedlings are 25 to 50 days old, they are transplanted to a field, or paddy, that has been enclosed by levees and submerged under 5 to 10 cm (2 to 4 inches) of water, remaining submerged during the growing season. In hilly areas, rice farms are commonly terraced to keep the paddies flooded at various elevations.

Successful rice production depends on adequate irrigation, including the construction of dams and waterwheels, and on the quality of the soil. Long periods of sunshine are essential. Rice yields vary considerably, ranging from 700 to 4,000 kilograms per hectare (600 to 3,500 pounds per acre). Adequate irrigation, which means the inundation of the fields to a depth of several inches during the greater part of the growing season, is a basic requirement for productive land use.

In Asia the paddy is cultivated in three main types of soil, including clays with a firm bottom within a few inches of the surface; silts and soft clays with soft bottoms becoming hard on drying; and peats and “mucks” containing peat, provided the depth of the peat is not excessive. Fields must be drained and dried before harvesting. When combine harvesters or binder threshers are employed, the grain must be dried to about 14 percent moisture so that no deterioration takes place in storage. When reaper binders are used, the crop is “shocked” in certain ways so that the grain is protected from rain.

Types of Rice

There are thousands of types of Oryza sativa, which can differ in size, thickness, stickiness, color, aroma, and flavor. Rice is often broadly categorized based on its shape or method of processing:

Long, Short, or Medium Grain

This refers to the length and width of the rice grain after cooking:

  1. Long grains have a slender kernel over four times as long as they are wide. When cooked, long-grain rice stays separate and fluffy (e.g., Jasmine and Basmati rice).
  2. Medium grains have a shorter, wider kernel, yielding a tender and semi-sticky consistency when cooked (e.g., Arborio rice).
  3. Short grains have a kernel only twice as long as they are wide, and yield the stickiest texture when cooked (e.g., “sushi” rice).

Whole or Refined Grain

Is the rice in its whole, intact form (like “brown” rice), or has it been milled and polished (like “white” rice)?

  1. Whole: Just like all whole grains, rice naturally contains three edible components—the bran, germ, and endosperm (the inedible hull is removed). “Brown” rice is the typical whole grain rice, though this describes not a particular variety but the natural color of the grain. However, whole grain rice is not limited to one color—it also comes in shades of black, purple, and red. Because the fibrous bran layer and nutrient-rich germ remain intact, these varieties typically take longer to cook, and have a nuttier and chewier texture than refined white rice.
  2. Refined: Rice that is polished to remove the bran layers and embryo so that only the starchy white endosperm remains—hence the name “white” rice (again, this refers to the color and not one particular variety). The milling and polishing process removes the majority of naturally occurring B vitamins, minerals, phytochemicals, and fiber, so B vitamins and iron are added back. Food labels will display the term “enriched” to indicate this. However, only a fraction of the original amount of these nutrients is added back.

Of course, when it comes to cooking, specific varieties of rice are often chosen for their unique characteristics. Here are a few popular types:

  • Arborio: A medium-grain rice popular for making risotto and puddings. It undergoes less milling than long-grain rice so it retains more starch, which is released during cooking to produce a naturally creamy consistency without becoming mushy. Unlike other rice cooking methods, water must be added to Arborio rice gradually in segments, with constant stirring, to produce the creamy texture of risotto. Arborio rice is available in both brown and white versions.
  • Basmati, Jasmine: These are varieties of long-grain rice with fragrant aromas that are available in both brown and white versions.
  • Black riceBlack (Forbidden), Purple, or Red: These types of short or medium-grain colorful rice contain a natural plant phytochemical called anthocyanins, a flavonoid with antioxidant properties that is also found in blueberries and blackberries. Their nutritious bran and germ layers are intact similar to brown rice.
  • Glutinous: Named for its glue-like consistency (not for gluten, which it does not contain), this short-grain rice is especially sticky when cooked. This is because it contains primarily one component of starch, called amylopectin, while other types of rice contain both amylopectin and amylose. Glutinous rice is particularly popular throughout Asia and is available in a range of colors including white, brown, and black/purple.
  • Sticky rice is short-grain rice used in many Asian cuisines. It is also known as glutinous rice or sweet rice. It can be ground into flour and used for dumplings. It is also used in making rice vinegar and Japanese sake.
  • Wild rice is the seed of an unrelated reed-like aquatic plant. It is typically used as a side dish and has more vitamins, minerals, and fiber than white rice varieties.
  • Wild pecan rice is unique long-grain rice that has a nutty flavor and rich aroma.

What Happens After Harvest?

Drying

dryingDrying is the process that reduces the grain moisture content to a safe level for storage. It is the most critical operation after harvesting a rice crop. Delays in drying, incomplete drying, or ineffective drying will reduce grain quality and result in losses.

Storage

Storing grain is done to reduce grain loss to weather, moisture, rodents, birds, insects, and micro-organisms. Usually, the rice should be stored in paddy form rather than milled rice as the husk provides some protection against insects. In the International Rice Genebank where rice seed from more than 118,000 different types of rice is conserved, the rice seed is kept in vacuum packed, freezers at -18 °C, where they can remain viable for 100 years.

Rice storage facilities take many forms depending on the quantity of grain to be stored, the purpose of storage, and the location of the store.

A good storage system should include:

  • protection from insects, rodents, and birds by allowing proper storage hygiene
  • ease of loading and unloading
  • efficient use of space
  • ease of maintenance and management
  • prevention of moisture re-entering the grain after drying
  • specific solutions to meet the challenges of storing rice in the humid tropics.

Milling

millingMilling is a crucial step in the post-production of rice. The basic objective of a rice milling system is to remove the husk and produce an edible, rice grain that is sufficiently milled and free of impurities. If only the husk is removed then ‘brown’ rice is the product. If the rice is further milled or polished then the bran layer is removed to reveal ‘white’ rice.

Depending on the requirements of the customer, the rice should have a minimum of broken grains.

A rice milling system can be a simple one-or two-step process or a multi-stage process. Depending on whether the paddy is milled in the village for local consumption or for marketing rice milling systems can be classified into the categories village rice mills and commercial mills.

Packaging and Transport

Once milled, rice is packed and transported to point of sale, which may be local or international.

Is rice a grain?

Rice is a cereal, related to other cereal grass plants such as wheat, oats, and barley.

It completes its entire life cycle within six months, from planting to harvesting. It’s also semi-aquatic, which means it can grow partly on land and partly submerged in water. Most cultivated rice comes from either the Oryza sativa, O. glaberrima, or O. rufipogon species.

Rice plants in the Riverina start their life as individual grains sown in irrigated fields that have been land-formed to maximize water productivity. They grow to become green, grassy plants about 60-100 cm tall. Each plant contains many heads full of rice grains that turn golden indicating the plant is ready to harvest.

Rice is generally divided into two types of species: Indica (adapted to tropical climates like South-East Asia) and Japonica (adapted to more temperate climates like in Australia). Indica varieties are usually characterized by having long, slender grains that stay separate and are fluffy once cooked, while Japonica varieties are smaller, round and when cooked are classed as ‘softer’ cooking and are sticky and moist. The Australian rice industry produces mostly Japonica types of rice, although some Indica characteristics have been introduced through a rice-breeding program.

What is in a grain of Rice?

The rice grain is made of three main layers – the hull or husk, the bran and germ, and the inside kernel, or endosperm.

The hull: The rice hull or husk is a hard, protective outer layer that people cannot eat. The hull is removed when the grain is milled.

Rice bran: Underneath the hull is the bran and germ layer, which is a thin layer of skin that adheres it all together. This layer gives brown rice its color. White rice is just brown rice with the bran and germ layer removed.

Endosperm: The endosperm is the inside of the rice grain, which is hard and white and contains lots of starch.

Rice Processing and Uses

The harvested rice kernel, known as paddy, or rough, rice, is enclosed by the hull, or husk. Milling usually removes both the hull and bran layers of the kernel, and a coating of glucose and talc is sometimes applied to give the kernel a glossy finish. Rice that is processed to remove only the husks, called brown rice, contains about 8 percent protein and small amounts of fats and is a source of thiamine, niacin, riboflavin, iron, and calcium.

Rice that is milled to remove the bran as well is called white rice and is greatly diminished in nutrients. When white rice forms a major portion of the diet, there is a risk of beriberi, a disease resulting from a deficiency of thiamine and minerals. Parboiled white rice is specially processed before milling to retain most of the nutrients, and enriched rice has iron and B vitamins added to it.

The milling methods used in most of Asia remain fairly primitive, but large mills operate in Japan and some other areas. Hulling of the paddy is usually accomplished by pestle and mortar worked by hand, foot, or water power. Improvements are slowly taking place. The yield of milled rice is dependent on the size and shape of the grain, the degree of ripeness, and the extent of exposure to the sun.

Some large mills, handling 500 to 1,000 tons of paddy daily, have specialized hulling plants with consequent smaller losses from broken grain. They generally employ modern milling techniques and rely on controlled drying plants instead of sun drying.

The by-products of milling, including the bran and rice polish (finely powdered bran and starch resulting from polishing), are sometimes used as livestock feed. Oil is processed from the bran for both food and industrial uses. Broken rice is used in brewing, distilling, and in the manufacture of starch and rice flour.

Hulls are used for fuel, packing material, industrial grinding, fertilizer manufacture, and in the manufacture of an industrial chemical called furfural. The straw is used for feed, livestock bedding, roof thatching, mats, garments, packing material, and broom straws.

Rice Nutrition Facts

The following nutrition information is provided by the USDA for 1 cup (186g) of cooked, enriched, short-grain white rice.

  • Calories: 242
  • Fat: 0.4g
  • Sodium: 0mg
  • Carbohydrates: 53.4g
  • Fiber: 0.6g
  • Sugars: 0g
  • Protein: 4.4g

Health Benefits And Effects

Rice can be part of a balanced diet, particularly if you choose the unprocessed, brown rice varieties. Many of the health benefits of rice come from the vitamins and minerals that it provides.

Supports Bones, Nerves, and Muscles

Magnesium is the structural component of bones that assists in hundreds of enzyme reactions involved in the synthesis of DNA and proteins and is required for proper nerve conduction and muscle contraction.

Improves Colon Health

Rice contains resistant starch, which can lead to the formation of certain fatty acids that help the colon stay healthy. These fatty acids may also decrease the risk of colorectal cancer.

Lowers Risk of Heart Disease

Consuming whole grains, including brown rice, is associated with a decreased risk of cardiovascular disease. The American Heart Association recommends making sure that at least half of the grains you eat are whole grains—so, aim to choose brown rice over white and 100% whole wheat bread over white bread most of the time.

Safe for People with Celiac Disease

Rice is a naturally gluten-free grain so it is useful to people with celiac disease and non-celiac sensitivity. Rice can be made into flour, noodles, bread, and syrup. It can also be made into milk and used as a non-dairy substitute for cow’s milk.

Provides Quick Energy

Athletes who need a lot of energy in the form of carbohydrates can get it from white rice. Many prefer white rice over brown for its high-carb, low-fiber profile.

Allergies

Although rice allergy is uncommon, it is possible. Allergy to rice is more common in Asian countries where rice is a big part of the typical diet. People with a rice allergy may also be sensitive to corn, soy, and barley, or vice versa.

Adverse Effects

Rice is one of the most common triggers for food protein-induced enterocolitis syndrome (FPIES). The condition usually affects babies and small children and is marked by inflammation of the small and large intestines. It is not actually an allergy, though it can look like one. Symptoms include gastrointestinal distress such as vomiting, diarrhea, and in severe cases even shock.

Sometimes rice can be contaminated with toxic heavy metals, such as cadmium, lead, mercury, and arsenic. This is especially of concern for babies and small children, which is why the FDA now limits arsenic levels in infant rice cereal.

Productivity in Global Rice Environments

Rice is grown in more than a hundred countries, with a total harvested area of approximately 158 million hectares, producing more than 700 million tons annually (470 million tons of milled rice). Nearly 640 million tons of rice are grown in Asia, representing 90% of global production. Sub-Saharan Africa produces about 19 million tons and Latin America some 25 million tons. In Asia and sub-Saharan Africa, almost all rice is grown on small farms of 0.5−3 ha.

Yields range from less than 1 t/ha under very poor rainfed conditions to more than 10 t/ha in intensive temperate irrigated systems. Small, and in many areas shrinking, farm sizes account for the low incomes of rice farm families. Rice grows in a wide range of environments and is productive in many situations where other crops would fail.

The highest rice yields have traditionally been obtained from plantings in high-latitude areas that have long day lengths and where intensive farming techniques are practiced, or in low-latitude desert areas that have very high solar energy. Southwestern Australia, Hokkaido in Japan, Spain, Italy, northern California, and the Nile Delta provide the best examples.

Global Rice Production and Consumption

Global-rice-production more than anywhere else in the world, rice dominates overall crop production (measured by the share of crop area harvested of rice) and overall food consumption (measured by the share of rice in total caloric intake) in rice-producing Asia.

The world’s largest rice producers by far are China and India. Although its area harvested is lower than India’s, China’s rice production is greater due to higher yields because nearly all of China’s rice area is irrigated, whereas less than half of India’s rice area is irrigated. After China and India, the next largest rice producers are Indonesia, Bangladesh, Vietnam, Myanmar, and Thailand. These seven countries all had average production in 2006-08 of more than 30 million tons of paddy and together account for more than 80% of world production.

Despite Asia’s dominance in rice production and consumption, rice is also very important in other parts of the world. In Africa, for example, rice has been the main staple food – defined as the food, among the three main crops, that supplies the largest amount of calories – for at least 50 years in parts of western Africa and for some countries in the Indian Ocean.

In these countries, the share of calories from rice has generally not increased substantially over time. In other African countries, however, rice has displaced other staple foods because of the availability of affordable imports from Asia and rice’s easier preparation, which is especially important in urban areas. On balance, in Africa, production has grown rapidly, but rice consumption has grown even faster, with the balance being met by increasing quantities of imports.

Western Africa is the main producing subregion, accounting for more than 40% of African production in 2006-08. In terms of individual countries, the leading producers of paddy (2006-08) are Egypt (7.0 million t), Nigeria (3.8 million t), and Madagascar (3.2 million t).

In Latin America and the Caribbean, rice was a preferred pioneer crop in the first half of the 20th century in the savannas of Brazil, Bolivia, Colombia, Uruguay, and Venezuela, and in forest margins throughout the region. Today, rice is the most important source of calories in many Latin American countries, including Ecuador and Peru, Costa Rica and Panama, Guyana and Suriname, and the Caribbean nations of Cuba, Dominican Republic, and Haiti.

It is less dominant in consumption than in Asia, however, because of the importance of wheat, maize, and beans in regional diets. Brazil is by far the largest producer, and it accounts for nearly half (46% in 2006-08) of paddy production in the region. After Brazil (11.6 million t), the largest producers are Peru and Colombia (2.5 million t each in 2006-08), followed by Ecuador (1.6 million t).

Elsewhere, the most important production centers are in the United States (California and the southern states near the Mississippi River), which produced 9.0 million t of paddy on average in 2006-08. The leading European producers are Italy, Spain, and Russia. Australia used to be an important producer, but its output has declined substantially in recent years because of recurring drought.

Rice consumption in the Pacific islands has increased rapidly over the past two decades. Rice, which is all imported apart from a small amount grown in Papua New Guinea, is displacing traditional starchy root crops as a major staple due to changing tastes, ease of storage and preparation, and sometimes cost.

Yield Improvement Practices

High-yieldingDevelopment of high-yielding varieties: The Green Revolution

The ‘Green Revolution’ is the name given to the dramatic increase in cereal crop yields through modern agricultural inputs – irrigation, fertilizers, improved seeds, and pesticides – in the 1960s. For rice, the revolution began with the release by IRRI of the high-yielding semidwarf variety IR8 in 1966. The world average rice yield in 1960, the product of thousands of years of experience, was about 2 t/ha. Astonishingly, in only 40 more years, as the Green Revolution spread, it doubled, reaching 4 t/ha in 2000. The rice varieties and technologies developed during the Green Revolution have increased yields in some areas to 6–10 t/ha.

Widespread hunger and malnutrition, especially in Asia, made it clear that the production of wheat and rice needed to increase to avoid famine.

The crisis led directly to the establishment of IRRI in 1960 and later its sister institutions in the Consultative Group on International Agricultural Research (CGIAR) system.

Fine-tuning the technologies

Irrigation and fertilizer helped raise cereal yields, but their full impact was realized only after the development of high-yielding varieties (HYVs). These semi-dwarf rice varieties were more responsive to plant nutrients and had a shorter and stiffer straws that would not fall over under the weight of heavier heads of grain. They also could mature more quickly and be insensitive to daylight length, thereby permitting more crops to be grown each year on the same land.

The first of these HYVs, named IR8, was released in 1966. Adoption of HYVs occurred quickly and about 40% of the total cereal area in Asia was planted to modern varieties by 1980. This increased to about 80% of the cropped area by 2000.

Although many of the initial HYV rice varieties dramatically raised yields, they were susceptible to pests and diseases and had cooking traits that were less appealing to consumers. Continuing investments in agricultural research led to the eventual development of second-and third-generation varieties that successfully combined high yield potential with good pest and disease resistance and preferred consumption traits.

Policy framework

Although the Green Revolution was mainly a technology revolution, it required strong public support and policies to develop the technologies, build the required infrastructure, ensure that markets, finance, and input systems worked and that farmers had enough knowledge and economic incentive to adopt the new practices. Public interventions were especially crucial in Asia for ensuring that small farmers were not left behind, and without which the Green Revolution would have been much less pro-poor. On average, Asian countries were spending 15.4% of their total government spending on agriculture by 1972 and they doubled the real value of their agricultural expenditure by 1985.

Governments also shored up farm credit systems, subsidized key inputs – especially fertilizer, power, and water – and intervened in markets to ensure that farmers received adequate prices each year to make the technologies profitable. Many governments used their interventions to ensure that small farms did not get left behind. Substantial empirical evidence at the time showed that small farms were the more efficient producers in Asia and land reform and small farm development programs were implemented to create and support large numbers of small farms. Small farm–led agricultural growth proved to be not only more efficient but also more pro-poor, a win-win proposition for growth and poverty reduction.

Impact of the Green Revolution

The Green Revolution not only increased yields, it also reduced the production costs per kg of cereal harvested. This enabled a win-win outcome in which cereal prices could decline to the benefit of consumers even while farmers and agricultural workers increased their earnings.

However, the relationship between the Green Revolution and poverty alleviation is complex, and this has led to a large and contentious debate in the literature. Village and household studies conducted soon after the release of Green Revolution technologies raised concern that large farms were the main beneficiaries of the technologies and that poor farmers were either unaffected or made worse off.

However, some studies have found favorable longer-term impacts on inequality.

Production, Area, and Yield Trends Over Time

Global rice production more than tripled between 1961 and 2010, with a compound growth rate of 2.24% per year (2.21% in rice-producing Asia). Most of the increase in rice production was due to higher yields, which increased at an annual average rate of 1.74%, compared with an annual average growth rate of 0.49% for the area harvested. In absolute terms, paddy yields increased at an annual average rate of 51.1 kg/ha per year, although this rate of increase has declined in both percentage and absolute terms.

The recent slowdown in the rice area and yield growth

production-challenges real yields have continued to rise on average across Asia since the Green Revolution era, but annual growth rates are slowing. Moreover, total factor productivity has been declining, meaning that farmers now have to use higher amounts of inputs to obtain the same yields as before. Fortunately, as the figure shows, population growth in rice-producing Asia has been steadily declining for even longer.

Since population growth has been the main source of rice demand growth, this trend helped to keep rice prices in check for a time. But, since the mid-1990s, population growth has exceeded rice yield growth and the gap has been growing steadily larger, creating a significant imbalance between supply and demand.

This trend is evident for Asia as a whole, but also separately for East Asia, Southeast Asia, and South Asia. Stagnation in the area harvested further contributed to the problem, and prices eventually began to rise. Indeed, world market rice prices rose steadily by a cumulative 67% between April 2001 and September 2007, even before the world price crisis.

There are several possible reasons for the slowdown in rice yield growth and production: displacement of cereals on better lands by more profitable crops such as groundnuts, diminishing returns to modern varieties when irrigation and fertilizer use are already high, and the fact that cereal prices have fallen relative to input costs, making additional intensification less profitable. There is also concern that pest and disease resistance to modern pesticides now slows yield growth, and that breeders have largely exploited the yield potential of major Green Revolution crops.

Environmental problems that have arisen in different areas include excessive and inappropriate use of fertilizers and pesticides that pollute waterways and kill beneficial insects and other wildlife, irrigation practices that lead to salt buildup and eventual abandonment of some of the best farming lands, increasing water scarcities in major river basins, and retreating groundwater levels in areas where more water is being pumped for irrigation than can be replenished.

Some of these outcomes were inevitable as millions of largely illiterate farmers began to use modern inputs for the first time, but the problem was exacerbated by inadequate extension and training, an absence of effective regulation of water use and quality, and input pricing and subsidy policies that made modern inputs too cheap and encouraged their excessive use.

Production challenges

Global rice consumption remains strong, driven by both population and economic growth in many Asian and African countries. But, in some developing Asian nations, including India, Vietnam, and Indonesia, per capita consumption in recent years has started to decline at a rather slow pace with rising income. In another middle- to low-income Asian countries, including the Philippines, Myanmar, Cambodia, Bangladesh, and Laos, rice consumption per capita continues to rise over time.

Despite this variation in the Asian per capita rice consumption trend, it is widely expected that per capita consumption in a majority of Asian countries will start or continue to decline in the future with rising income as people diversify their diets. But there are exceptions, such as India with its large population of over-vegetarians, where rice consumption patterns may not change dramatically even as income rises and a rapid increase in urbanization influences food habits.

Outside Asia, where rice is not a staple yet, per capita consumption continues to grow. This is particularly true for most countries in sub-Saharan Africa, where high population growth with changing consumer preferences is causing rapid expansion in rice consumption. In the least developed countries such as Nigeria, Tanzania, and Niger, people are moving away from tubers and cassava to rice as their income rises.

Similar strong consumption growth has been evident among Middle Eastern countries with almost doubling of rice consumption in the last two decades and even more rapid increases in some Pacific island countries. Along with strong population growth, the rapid rise in per capita consumption also contributed to such rapid growth in rice demand.

Rice consumption also continues to grow in Latin America and the Caribbean region with a 40% increase in the last two decades as a combination of both population growth and the steady rise in per capita consumption. Even in developed countries/regions, such as the United States and the European Union, per capita consumption continues to grow, partly because of switching from protein to more fibers in the diet and also immigration from Asian countries.

Using the population projections from the United Nations and income projections from the Food and Agricultural Policy Research Institute (FAPRI), global rice demand is estimated to rise from 439 million tons (milled rice) in 2010 to 496 million tons in 2020 and further increase to 555 million tons in 2035. This is an overall increase of 26% in the next 25 years, but the rate of growth will decline from 13% for the first 10 years to 12% in the next 15 years as population growth drops and people diversify from rice to other foods.

Among the various rice-consuming regions, Asian rice consumption is projected to account for 67% of the total increase, rising from 388 million tons in 2010 to 465 million tons in 2035 despite a continuing decline in per capita consumption in China and India. In addition, 30 million tons more rice will be needed by Africa, an increase of 130% from 2010 rice consumption. In the Americas, total rice consumption is projected to rise by 33% over the next 25 years.

With further area expansion likely to be slow, global rice yields must rise faster than in the recent past if world market prices are to be stabilized at affordable levels for the billions of consumers. Globally, farmers need to produce at least 8–10 million tons more paddy rice each year—an annual increase of 1.2–1.5% over the coming decade, equivalent to an average yield increase of 0.6 t/ha during the next decade.

Over the longer run, global rice consumption growth is expected to slow down but yields will have to continue to grow faster than at present because of pressure on rice lands in the developing world from urbanization, climate change, and competition from other, high-value agriculture. Rice yield growth of 1.0–1.2% annually beyond 2020 will be needed to feed the still-growing world and keep prices affordable.

Read More: Modern Chinese Rice Production Technology Is Favorable In Pakistan

Common Pests and Diseases

Diseases

  • Bacterial leaf streak Xanthomonas oryzae
  • Leaf scald Microdochium oryzae
  • Rice Bacterial blight Xanthomonas oryzae pv. oryzae
  • Bakanae Fusarium moniliforme
  • Brown spot Cochliobolus miyabeanus
  • False smut Ustilaginoidea virens
  • Narrow leaf spot (Cercospora leaf spot) Cercospora oryzae
  • Rice blast Magnaporthe grisea
  • Sheath blight Rhizoctonia solani
  • Stem rot Magnaporthe salvinii
  • Grassy stunt Rice grassy stunt virus (RGSV)
  • Tungro Rice tungro bacilliform virus (RTBV)

Pests

  • Leafhoppers & planthoppers Nephotettix spp.
  • Mole cricket Gryllotalpa orientalis
  • Rice bug Leptocorisa oratorius F. and Leptocorisa acuta Thunberg
  • Rice case worm Paraponyx stagnalis Stagnalis (Lepidoptera : Pyralidae)
  • Rice gall midge Orseolia oryzae
  • Rice mealy bugs Brevennia rehi
  • Stem borers (Yellow stem borer, Striped stem borer, White stem borer, etc.) Scirpophaga incertulas, Chilo suppressalis, Scirpophaga innotata

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 (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 the 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 is conducted during weddings in Nepal. The bride gives a leaf plate full of pounded rice to the groom after he requests it politely from her.

In the Philippines rice wine, popularly known as tapuy, 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, and Balinese people 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 structured, mainstream religion.

The same female rice deity is known as Po Ino Nogar in Cambodia and as Nang Khosop in Laos. 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.

Source: Britannica, Harvard College, Very Well Fit, Ricepedia, Sunrice, Plant Village, Wikipedia, Agropedia

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