Rice is a cereal grain and in its domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species Oryza sativa —or, much less commonly, Oryza glaberrima. Asian rice was domesticated in China some 13,500 to 8,200 years ago; African rice was domesticated in Africa about 3,000 years ago. Rice has become commonplace in many cultures worldwide; in 2021, 787 million tons were produced, placing it fourth after sugarcane, maize, and wheat. Only some 8% of rice is traded internationally. China, India, and Indonesia are the largest consumers of rice. A substantial amount of the rice produced in developing nations is lost after harvest through factors such as poor transport and storage. Rice yields can be reduced by pests including insects, rodents, and birds, as well as by weeds, and by diseases such as rice blast. Traditional rice polycultures such as rice-duck farming, and modern integrated pest management seek to control damage from pests in a sustainable way.
Oryza is a genus of plants in the grass family. It includes the major food crop rice. Members of the genus grow as tall, wetland grasses, growing to 1–2 metres (3–7 ft) tall; the genus includes both annual and perennial species.
Oryza sativa, having the common name Asian cultivated rice, is the much more common of the two rice species cultivated as a cereal, the other species being O. glaberrima, African rice. It was first domesticated in the Yangtze River basin in China 13,500 to 8,200 years ago.
Basmati is a variety of long, slender-grained aromatic rice which is traditionally grown in the Indian subcontinent, mainly India, and Pakistan, as well as some regions of Sri Lanka and Nepal. As of 2019, India accounted for 65% of the international trade in basmati rice, while Pakistan accounted for the remaining 35%. Many countries use domestically grown basmati rice crops; however, basmati is geographically exclusive to certain districts of India and Pakistan.
Jasmine rice is a long-grain variety of fragrant rice. Its fragrance, reminiscent of pandan and popcorn, results from the rice plant's natural production of aroma compounds, of which 2-acetyl-1-pyrroline is the most salient. A rapid loss of aromatic intensity leads many Southeast Asians and connoisseurs to prefer each year's freshly harvested "new crop" of jasmine rice. Jasmine rice is a variety of Oryza sativa.
The brown planthopper (BPH), Nilaparvata lugens (Stål) is a planthopper species that feeds on rice plants. These insects are among the most important pests of rice, which is the major staple crop for about half the world's population. They damage rice directly through feeding and also by transmitting two viruses, rice ragged stunt virus and rice grassy stunt virus. Up to 60% yield loss is common in susceptible rice cultivars attacked by the insect. The BPH is distributed throughout Australia, Bangladesh, Bhutan, Burma (Myanmar), Cambodia, China, Fiji, India, Indonesia, Japan, North and South Korea, Laos, Malaysia, India, Nepal, Pakistan, Papua New Guinea, Philippines, Sri Lanka, Taiwan, Thailand, and Vietnam. Their alternative host plant other than rice is Leersia hexandra.
Wehani rice, also known as California Red Jasmine Rice, is a variety of aromatic brown rice developed in the late 20th century by Lundberg Family Farms of Richvale, California. The name of the rice originates from the brothers of the family, Wendell, Eldon, Homer, Albert, and Harlan Lundberg.
Oryza rufipogon is a species of flowering plant in the family Poaceae. It is known as brownbeard rice, wild rice, and red rice. In 1965, Oryza nivara was separated off from O. rufipogon. The separation has been questioned, and some sources consider O. nivara to be a synonym of O. rufipogon. O. nivara may be treated as the annual form of O. rufipogon.
Oryza glaberrima, commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown in West Africa around 3,000 years ago. In agriculture, it has largely been replaced by higher-yielding Asian rice, and the number of varieties grown is declining. It still persists, making up an estimated 20% of rice grown in West Africa. It is now rarely sold in West African markets, having been replaced by Asian strains.
Oryza nivara is a possible wild progenitor of the cultivated rice Oryza sativa. It was separated from Oryza rufipogon in 1965; however, the separation has been questioned, and some sources treat it as a synonym of O. rufipogon. It may be treated as the annual form of O. rufipogon.
Japonica rice, sometimes called sinica rice, is one of the two major domestic types of Asian rice varieties. Japonica rice is extensively cultivated and consumed in East Asia, whereas in most other regions indica rice is the dominant type of rice. Japonica rice originated from Central China, where it was first domesticated along the Yangtze River basin approximately 9,500 to 6,000 years ago.
In statistical genetics, inclusive composite interval mapping (ICIM) has been proposed as an approach to QTL mapping for populations derived from bi-parental crosses. QTL mapping is based on genetic linkage map and phenotypic data to attempt to locate individual genetic factors on chromosomes and to estimate their genetic effects.
Plant breeding started with sedentary agriculture, particularly the domestication of the first agricultural plants, a practice which is estimated to date back 9,000 to 11,000 years. Initially, early human farmers selected food plants with particular desirable characteristics and used these as a seed source for subsequent generations, resulting in an accumulation of characteristics over time. In time however, experiments began with deliberate hybridization, the science and understanding of which was greatly enhanced by the work of Gregor Mendel. Mendel's work ultimately led to the new science of genetics. Modern plant breeding is applied genetics, but its scientific basis is broader, covering molecular biology, cytology, systematics, physiology, pathology, entomology, chemistry, and statistics (biometrics). It has also developed its own technology. Plant breeding efforts are divided into a number of different historical landmarks.
Xanthomonas oryzae pv. oryzae is a bacterial pathovar that causes a serious blight of rice, other grasses, and sedges.
Oryza australiensis is a wild rice species native to monsoonal northern Australia. Also known as Australian rice or Australian Wild Rice, it is a perennial plant that uses the C3 photosynthesis pathway. O. australiensis is unique among other Oryza for its resistance to abiotic stresses, particularly from heat, and having the largest genome in the genus.
Paw san hmwe is a high-grade variety of aromatic rice grown in Myanmar. Paw hsan hmwe is known for its good cooking quality, fragrant aroma, texture, good milling recovery, and substantial grain elongation during the cooking process. The medium-length grains of this rice variety can elongate up to three times in length while cooking. Paw hsan hmwe has intermediate amylose content, higher than jasmine rice, contributing to its hardness quality in line with Burmese consumer preferences. Myanmar's Paw San rice is one of the world's most recognized high quality rice, it was awarded the world's best rice at the Rice Trader's World Rice Conference in 2011. Paw San rice has a similar aroma, grain quality and eating quality to the reputable aromatic rice varieties of the world, namely Basmati of India and Pakistan and Jasmine of Thailand. It has a strong aroma similar to Jasmine rice and
Domestication syndrome refers to two sets of phenotypic traits that are common to either domesticated plants or domesticated animals.
The history of rice cultivation is an interdisciplinary subject that studies archaeological and documentary evidence to explain how rice was first domesticated and cultivated by humans, the spread of cultivation to different regions of the planet, and the technological changes that have impacted cultivation over time.
The agricultural weed syndrome is the set of common traits which make a plant a successful agricultural weed. Most of these traits are not, themselves, phenotypes but are instead methods of rapid adaptation. So equipped, plants of various origins - invasives, natives, mildly successful marginal weeds of agriculture, weeds of other settings - accumulate other characteristics which allow them to compete in an environment with a high degree of human management.
