Genetic Diversity Of Weedy and Cultivated Rice: Models For Evolution In Agroecosystems

Red rice is an aggressive, weedy form of cultivated rice (Oryza sativa) that infests crop fields and is a primary factor limiting rice productivity worldwide.  Capitalizing on the relatedness of red rice with a genomic model species, this project addresses the evolution of weediness through a combination of QTL mapping, genome-wide analyses of population structure, and candidate gene studies.  Here we present our findings on the population structure of weedy rice collected from Southeast Asia and two candidate genes, black hull4 (Bh4), a gene involved in hull color determination and phosphorus starvation tolerance 1 (PSTOL1), a gene involved in phosphorus efficiency.  Southeast Asian weeds appear to be far more genetically heterogeneous than North American red rice, potentially reflecting the greater diversity of reproductively compatible wild and cultivated germplasm in Asia.  Candidate gene sequencing offers additional insight into evolution of important rice traits in both weeds and crops.