Oryza sativa
Asian cultivated rice, a model cereal domesticated in ancient China.
Oryza sativa, commonly known as Asian cultivated rice, is one of two rice species cultivated as a cereal, the other being O. glaberrima (African rice). It was first domesticated in the Yangtze River basin in China between 13,500 and 8,200 years ago. This species belongs to the genus Oryza and the BOP clade within the grass family Poaceae. Its genome spans 430 million base pairs across 12 chromosomes, and it is valued as a model organism for studying cereal and monocot biology due to its ease of genetic modification. Domestication from the wild ancestor Oryza rufipogon involved selecting for a mutation that prevented seeds from shattering, making harvesting easier. Plants were also bred for an upright, vertical growth habit to maximize field density, and awns were selectively removed to reduce bulk. O. sativa subsequently diverged into two major subspecies: japonica and indica. Japonica, domesticated in the Yangtze Valley, is shorter with darker leaves and produces short, round, plump grains low in amylose; it is grown in temperate and subtropical regions, as well as upland areas of Southeast Asia and high elevations in South Asia. Indica, domesticated around the Ganges, is taller with lighter leaves and yields thinner, longer grains high in amylose; it is primarily a lowland rice grown submerged throughout tropical Asia. A third subspecies, tropical japonica (formerly javanica), is broad-grained and thrives in tropical conditions, exemplified by cultivars like Tinawon and Unoy from the Philippine rice terraces. Rice grain occurs in white, brown, black (purple when cooked), and red varieties.
- field
- Botany, agriculture, genetics
- known_for
- Major cereal crop; model organism for cereal and monocot biology; easy to genetically modify
- domestication_region
- Yangtze River basin, China
Lore & Background
It contains two major subspecies: japonica (sticky, short-grained) and indica (nonsticky, long-grained). A third subspecies, tropical japonica (formerly javanica), is broad-grained and thrives under tropical conditions, with examples like 'Tinawon' and 'Unoy' grown in Philippine high-elevation rice terraces. The plant itself has an erect, smooth stalk that grows tall, with lanceolate leaves emerging from a ligule. Domestication from the wild ancestor *Oryza rufipogon* involved selecting for non-shattering seeds, which kept grains attached for easier harvest, and for a more vertical growth architecture to maximize field density. Awns were also bred away to reduce bulk. *O. sativa* subsp. *japonica*, domesticated in the Yangtze Valley, is shorter with darker leaves and produces short, round, plump grains lower in amylose. It is grown in temperate and subtropical regions, including dry fields and high elevations. *O. sativa* subsp. *indica*, domesticated around the Ganges, is taller with lighter leaves and yields thinner, longer grains higher in amylose; it is primarily a lowland rice grown submerged in tropical Asia. Rice grain color varies widely, including white, brown, black (purple when cooked), and red.
Reader's Guide
Oryza sativa is one of the world's most important cereal crops, feeding billions. Its domestication in the Yangtze River basin over 8,000 years ago marks a pivotal event in human agricultural history. The species is renowned for being easy to genetically modify, making it a model organism for studying cereal and monocot biology. Genetic resistance to rice blast fungus (Magnaporthe grisea) is provided by genes including Pi1, Pi54, and Pita, with immune responses regulated by abscisic acid and salicylic acid. Insect resistance genes, particularly for brown planthopper, have been cloned, and adaptations to flooding include the Sub1 locus on chromosome 9 and SNORKEL genes for deepwater rice.
Did You Know?
- The species contains two major subspecies: japonica (sticky, short-grained) and indica (nonsticky, long-grained).
- Resistance to rice blast fungus is provided by genes including Pi1, Pi54, and Pita.
Frequently Asked Questions
Who is Oryza sativa?
Oryza sativa is the scientific name for Asian cultivated rice, one of just two rice species humans grow as a cereal grain (the other being African rice, O. glaberrima). It sits in the grass family Poaceae under the genus Oryza.
What is Oryza sativa's role in the world?
It is a major cereal crop that feeds billions of people across the globe. Beyond the field, it also serves as a key model organism for understanding cereal and monocot biology.
Why do scientists love working with Oryza sativa?
It is notably easy to genetically modify, which makes it a favorite model for studying how cereal and monocot traits work. Insights gained in rice labs often translate to improving other food crops.
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