''Oryza sativa'', having the common name Asian cultivated rice, is the much more common of the two

rice Rice is a cereal grain and in its Domestication, 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'' (Asian rice)—or, much l ...

species cultivated as a

cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

, 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. ''Oryza sativa'' belongs to the genus ''

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 annua ...

'' and the BOP clade in the grass family

Poaceae Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivate ...

. With a

genome A genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as ...

consisting of 430 Mbp across 12

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

s, it is renowned for being easy to genetically modify and is a

model organism A model organism 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 workings of other organisms. Mo ...

for the study of the biology of

s and monocots.

Description

''O. sativa'' has an erect stalk stem that grows tall, with a smooth surface. The leaf is lanceolate, long, and grows from a

ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above g ...

long. Image:Kerbau Jawa.jpg,

Water buffalo The water buffalo (''Bubalus bubalis''), also called domestic water buffalo, Asian water buffalo and Asiatic water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also kept in Italy, the Balkans ...

ploughing a rice paddyfield,

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

File:Jumli Marshi Oryza sativa Rice.jpg, Jumli Marshi, brown rice from Nepal File:Niyamgiri rice.jpg, Traditional rice of Niyamgiri Hills, India File:Medicinal Rice.jpg, From

Chhattisgarh Chhattisgarh (; ) is a landlocked States and union territories of India, state in Central India. It is the List of states and union territories of India by area, ninth largest state by area, and with a population of roughly 30 million, the List ...

File:Koeh-232.jpg, File:RiceStemcs400x1.jpg, Stem cross section magnified 400 times

Classification

The generic name ''

'' is a classical Latin word for rice, while the specific epithet ''

sativa Sativa, sativus, and sativum are Latin botanical adjectives meaning '' cultivated''. It is often associated botanically with plants that promote good health and used to designate certain seed-grown domestic crops. Usage ''Sativa'' (ending in -a) ...

'' means "cultivated". ''Oryza sativa'' contains two major subspecies: the sticky, short-grained ''japonica'' or ''sinica'' variety, and the nonsticky, long-grained ' rice variety. ''Japonica'' was domesticated in the Yangtze Valley 6,000–9,000 years ago, and its varieties can be cultivated in dry fields (it is cultivated mainly submerged in Japan), in temperate East Asia, upland areas of Southeast Asia, and high elevations in South Asia, while ''indica'' was domesticated around the

Ganges The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary rive ...

4,500–8,500 years ago, and its varieties are mainly lowland rices, grown mostly submerged, throughout tropical Asia. Rice grain occurs in a variety of colors, including

white White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

brown Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors Orange (colour), orange and black. In the ...

black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...

(purple when cooked), and red. A third subspecies, which is broad-grained and thrives under tropical conditions, was identified based on morphology and initially called ''javanica'', but is now known as ''tropical japonica''. Examples of this variety include the medium-grain 'Tinawon' and 'Unoy' cultivars, which are grown in the high-elevation rice terraces of the Central Cordillera Mountains of northern

Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...

, Philippines. Glaszmann (1987) used isozymes to sort ''O. sativa'' into six groups: '' japonica'', ''aromatic'', ''indica'', ''aus'', ''rayada'', and ''ashina''. Garris ''et al.'' (2004) used simple sequence repeats to sort ''O. sativa'' into five groups: '' temperate japonica'', ''tropical japonica'' and ''aromatic'' comprise the ''japonica'' varieties, while ''indica'' and ''aus'' comprise the ''indica'' varieties. The Garris scheme has held up against newer analyses as of 2019, though one 2014 article argues that ''rayada'' is distinct enough to be its own group under ''japonica''.

Genetics

/ is a gene that regulates the overall

architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and construction, constructi ...

/ growth habit of the plant. Some of its epialleles increase rice yield. An accurate and usable simple sequence repeat marker set was developed and used to generate a high-density map. A multiplex high-throughput marker assisted selection system has been developed but as with other crop HTMAS systems has proven difficult to customize, costly (both directly and for the equipment), and inflexible. Other molecular breeding tools have produced rice blast resistant cultivars. DNA microarray has been used to advance understanding of

hybrid vigor Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a Hybrid (biology), hybrid offspring. An offspring is heterotic if its trait (biology), traits are enhanced as a result of m ...

in rice, QTL sequencing has been used to elucidate seedling vigor, and genome wide association study (GWAS) by

whole genome sequencing Whole genome sequencing (WGS), also known as full genome sequencing or just genome sequencing, is the process of determining the entirety of the DNA sequence of an organism's genome at a single time. This entails sequencing all of an organism's ...

(WGS) has been used to investigate various agronomic traits. In total, 641 copy number variations are known. Exome capture often reveals new single nucleotide polymorphisms in rice, due to its large genome and high degree of DNA repetition. Resistance to the rice blast fungus '' Magnaporthe grisea'' is provided by various resistance genes including ', ', and '. ''O. sativa'' uses the plant hormones abscisic acid and salicylic acid to regulate immune responses. Salicylic acid broadly stimulates, and abscisic acid suppresses, immunity to ''M. grisea''; success depends on the balance between their levels. ''O. sativa'' has a large number of insect resistance genes specifically for the brown planthopper. , 15 R genes have been cloned and characterized.

References

External links

* * {{Authority control

Crops originating from Asia Flora of China Plants described in 1753 Rice Taxa named by Carl Linnaeus

Description

Classification

Genetics

See also

References

External links