Weed Science (2012) 60, 451-461

David H. Gealy, Hesham Agrama and Melissa H. Jia (2012)
Genetic analysis of atypical U.S. red rice phenotypes: Indications of prior gene flow in rice fields?
Weed Science 60 (3), 451-461
Abstract: Weedy red rice is a troublesome weed problem in rice fields of the southern United States. Typically, red rice plants are much taller than rice cultivars, and most biotypes are either awnless with straw-colored hulls (strawhull) or have long awns with black-colored hulls (blackhull). Outcrossing between rice and red rice occurs at low rates, resulting in a broad array of plant types. Simple sequence repeat (SSR) markers were used to evaluate the genetic backgrounds of atypical red rice types obtained from rice farms in Arkansas, Louisiana, Missouri, and Mississippi, in comparison to standard red rice types and rice cultivars. Principal coordinates analysis (PCoA) and population structure analysis of atypical red rice accessions suggested that short-stature awnless (LhtsA−) and awned (LhtsA+) types, each representing a total of about 5% of a 460-accession collection, usually were closely genetically related to their normal-sized counterparts, and not with cultivated rice. A short-awned, intermediate height type, 'Sawn', representing about 4% of the accessions was genetically distinct from all of the other types. Key alleles in Sawn types appeared to be shared by both standard awnless (StdRRA−) and awned (StdRRA+) red rice, suggesting that Sawn types could have arisen from gene flow between awned and awnless red rice types.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): David R. Gealy, Hesham A. Agrama

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Oryza (weeds)	Rice (Oryza)	U.S.A. (mid N)
	Oryza (weeds)	Rice (Oryza)	U.S.A. (mid S)