ARS | Publication request: The origin of weediness in U.S. red rice

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 1, 2010
Publication Date: January 9, 2010
Citation: Caicedo, A.L., Reagon, M., Thurber, C.S., Olsen, K.L., Gross, B.L., Jia, Y. 2010. The origin of weediness in U.S. red rice [abstract]. Plant and Animal Genome Conference Proceedings, January 9-13, 2010, San Diego, California. Abstract W629.

Technical Abstract: Weedy or red rice, a congeneric weed of cultivated rice (Oryza sativa L.), is a significant problem throughout the world. Despite belonging to the same species complex as domesticated rice and its wild relatives, the evolutionary origins of weedy rice remain unclear. We have used genome-wide and candidate locus patterns of single nucleotide polymorphism (SNP) variation in a broad Oryza sample to infer the origin and demographic processes influencing weedy rice evolution in the U.S. We find great population structure, with genetically divergent populations having separate origins. The two main U.S. weedy rice populations share genetic background with cultivated O. sativa varieties not grown commercially in the U.S., suggesting weed origins from domesticated ancestors. A domestication origin is further supported by genealogical relationships among weedy and cultivated alleles at an important domestication locus. Demographic simulations indicate large differences among main weedy groups in the severity of bottlenecks upon their establishment in the U.S., and in the timing of divergence from their cultivated relatives. The diverse origins of U.S. weedy rice populations demonstrate the multiplicity of evolutionary forces that can influence the emergence of weeds from a single species complex.