''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 The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...

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 The BOP clade (sometimes ''BEP clade'') is one of two major lineages (or clades) of undefined taxonomic rank in the grasses (Poaceae), containing more than 5,400 species, about half of all grasses. Well-known members of this clade include rice, ...

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 Monocotyledons (), commonly referred to as monocots, ( Lilianae '' sensu'' Chase & Reveal) are flowering plants whose seeds contain only one embryonic leaf, or cotyledon. A monocot taxon has been in use for several decades, but with various ranks a ...

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 Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture and engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **A ...

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 The Yangtze or Yangzi ( or ) is the longest river in Eurasia and the third-longest in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows including Dam Qu River the longest source of the Yangtze, i ...

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 Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–750 nanometres. It is a primary color in the RGB color model and a seconda ...

. 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

terrace Terrace may refer to: Landforms and construction * Fluvial terrace, a natural, flat surface that borders and lies above the floodplain of a stream or river * Terrace, a street suffix * Terrace, the portion of a lot between the public sidewalk a ...

s 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

isozyme In biochemistry, isozymes (also known as isoenzymes or more generally as multiple forms of enzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters (e.g. di ...

s to sort ''O. sativa'' into six groups: '' japonica'', ''aromatic'', ''indica'', ''aus'', ''rayada'', and ''ashina''. Garris ''et al.'' (2004) used

simple sequence repeat A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. T ...

s 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 Habit, equivalent to habitus in some applications in biology, refers variously to aspects of behaviour or structure, as follows: *In zoology (particularly in ethology), ''habit'' usually refers to aspects of more or less predictable ''behaviour' ...

of the plant. Some of its

epiallele An allele is a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule. Alleles can differ at a single position through single nucleotide polymorphisms (SNP), but they can also have insertions and deletions ...

s increase rice yield. An accurate and usable

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 Molecular breeding is the application of molecular biology tools, often in plant breeding and animal breeding. In the broad sense, molecular breeding can be defined as the use of genetic manipulation performed at the level of DNA to improve traits ...

tools have produced

rice blast ''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 , is a plant-pathogenic fungus ...

resistant cultivars.

DNA microarray A DNA microarray (also commonly known as a DNA chip or biochip) is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or t ...

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 In genomics, a genome-wide association study (GWA study, or GWAS), is an observational study of a genome-wide set of genetic variants in different individuals to see if any variant is associated with a trait. GWA studies typically focus on assoc ...

(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 variation Copy number variation (CNV) is a phenomenon in which sections of the genome are repeated and the number of repeats in the genome varies between individuals. Copy number variation is a type of structural variation: specifically, it is a type of ...

s are known. Exome capture often reveals new

single nucleotide polymorphism In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in ...

s in rice, due to its large genome and high degree of DNA repetition. Resistance to the rice blast 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 , is a plant-pathogenic fungus ...

'' is provided by various resistance genes including ', ', and '. ''O. sativa'' uses the plant hormones

abscisic acid Abscisic acid (ABA or abscisin II) is a plant hormone. ABA functions in many plant developmental processes, including seed and bud dormancy, the control of organ size and stomatal closure. It is especially important for plants in the response to ...

and

salicylic acid Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...

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 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 ...

. , 15

R gene Resistance genes (R-Genes) are genes in plant genomes that convey plant disease resistance against pathogens by producing R proteins. The main class of R-genes consist of a nucleotide binding domain (NB) and a leucine rich repeat (LRR) dom ...

s 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