''Oryza rufipogon'' is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the 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 ...

''. 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 now many sources consider ''O. nivara'' to be a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''O. rufipogon''. ''O. nivara'' may be treated as the annual form of ''O. rufipogon''. It is native to East-, Southeast- and South- Asia. It has a close

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

ary relation to ''

Oryza sativa ''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 ''Oryza glaberrima, O. glaberrima'', African rice. It was History of rice cultivation ...

'', the plant grown as a major

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 ...

food crop throughout the world. ''Oryza nivara'' is a possible wild progenitor of cultivated rice. Both have an AA genome.

Description

For those who accept ''Oryza nivara'' as a separate species, it is an annual, short to intermediate height (usually <) grass; panicles usually compact, rarely open; spikelets large, long and wide, with strong awn ( long); anthers long. It grows in shallow water up to , in seasonally dry and open habitats. It is found growing in swampy areas, at edge of pond and tanks, beside streams, in ditches, in or around rice fields.

Genetics

Selection

As with a great many plants and animals, ''O. rufipogon'' has a positive correlation between

effective population size The effective population size (''N'e'') is the size of an idealised population that would experience the same rate of genetic drift as the real population. Idealised populations are those following simple one- locus models that comply with ass ...

and magnitude of selection pressure. ''O. r.'' having an EPS of ≈140,000, it clusters with others of about the same EPS, and has 78% of its

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

sites under selection.

Precious germplasm

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

, the Pallikaranai marshland contains the wild rice ''O. rufipogon'', described by the Sálim Ali Centre for Ornithology and Natural History (SACON) as a "precious germplasm."

Domestication

Dai ''et al.'', 2012 discover ', an allele of '/'. Dai also finds ''LHD1'' produces the late heading ''O. rufipogon''

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

. This is one of the traits bred out during ''O. sativa'' domestication.

Genome

The genome of ''O. nivara'' was first sequenced in 2015. : : :This review cites this research. : : Stein ''et al.'', 2018 sequenced the genomes of ''O. nivara'' and other

domesticated Domestication is a multi-generational mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, to obtain from them a steady supply of reso ...

and wild relatives. They produced reference assemblies and analyses for divergence time and

genetic distance Genetic distance is a measure of the genetics, genetic divergence between species or between population#Genetics, populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with ...

. (The ''O. nivara'' assembly is 338 Mb.) They demonstrated that this species and ''Oryza sativa'' subsp. ''indica'' are most closely related and that the same is true for ''Oryza sativa'' subsp. ''japonica'' and ''Oryza rufipogon''. : : : : :These reviews cite this research. : :

Invasive species

''Oryza rufipogon'' is an

invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

and listed as a '

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is harmful to agricultural or horticultural crops, natural habitats or ecosystems, or humans or lives ...

' by the United States, and listed as a noxious weed in

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, and

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. According to the NAPPO ( North American Plant Protection Organization), ''O. rufipogon'' blends in with cultivated ''O. sativa'' so well that it cannot be detected. In this position it competes with the cultivated rice and uses valuable

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

and space. ''O. rufipogon'' sheds most of its seeds before the harvest, therefore contributing little to the overall yield. In addition, the rice grains produced by the plant are not eaten by consumers, who see it as a strange foreign particle in otherwise white rice.NAPPO ( North American Plant Protection Organization ) - PRA / Grains Panel Pest Fact Sheet - ''Oryza rufipogon'' Griff. June / 2003, http://www.nappo.org/PRA-sheets/Oryzarufipogon.pdf

References

{{Taxonbar, from=Q2217322, from2=Q7105330 rufipogon Flora of China Flora of tropical Asia Flora of Australia Taxa named by William Griffith (botanist)