Population Structure and Genetic Diversity in Oryza rufipogon, the Ancestral Species of Cultivated Asian Rice

The wild ancestor of cultivated Asian rice, Orzya sativa, has historically been described as two separate species: O. rufipogon, a partially-outcrossing, aquatic perennial, and O. nivara, its inbreeding, annual counterpart, found in seasonally wet environments.  Both species are currently found in overlapping ranges across South and Southeast Asia and Oceania, and are cross-compatible with each other and with cultivated rice.  In order to better understand introgression, genetic diversity, and population structure in O.rufipogon/O. nivara germplasm, we have genotyped a geographically, morphologically and genetically diverse panel of ~270 O. rufipogon/O. nivara accessions representative of the publicly-available wild germplasm using SSR, MITE, and SINE marker sets, as well as sequence-based chloroplast polymorphisms.  Elucidating population structure and diversity in the extant representatives of the wild ancestor of rice will not only assist in genebank management, ecological conservation, and interspecific breeding strategies, but also provides a foundational understanding for working with these wild accessions in genome-wide association studies (GWAS) as part of our ongoing research.