Economic Botany: Evolution of Cultivated Plants
Londo, Jason , Schaal, Barbara .
Insights into the Origin and Population Genetics of Weedy Red Rice (Oryza sativa) in the United States.
Weedy red rice (Oryza sativa L) is a persistent and problematic weed of rice culture worldwide. A major hypothesis for the mechanism of production of this weed in south and south-east Asia is hybridization between cultivated rice (Oryza sativa) and wild rice (Oryza rufipogon). However, weedy red rice can often be found outside the native range of O. rufipogon, leaving questions on the origin and process behind weedy rice infestations. In the United States, weedy red rice was first documented as early as 1846 and has continued to affect rice production areas of the southern US and California. In this study, we attempt to identify the origin and population structure of weedy red rice sampled from the United States using both DNA sequence data from a neutral nuclear locus as well as microsatellite genotype data. Initial results indicate that two major forms of weedy rice exist in the US, strawhull and blackhull, and these forms may both hybridize with the cultivated rice of the United States, O. sativa japonica. Further analysis using principle component analysis as well as the program STRUCTURE was used to examine the multi-locus genotype signatures of weedy rice and infer the potential weedy rice origins. These results suggest three independent Asian origins and hybridizations for US weedy rice. Additionally, hybridization between strawhull and blackhull weedy rice was inferred and demonstrates the possibility for the production of new weedy forms in the future.
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1 - US-EPA Western Ecology Division, 200 SW 35th St, Corvallis, OR, 97333, USA
2 - Washington University, Department of Biology, 1 Brookings Drive, Rebstock Hall, St. Louis, Missouri, 63130, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Lake Ontario/Hilton
Date: Monday, July 9th, 2007
Time: 8:45 AM