Population Structure, Linkage Disequilibrium and Selective Loci in Natural Populations of Prunus davidiana

Prunus davidiana (Carrie're) Franch is a very important resource for the restoration in dry and arid areas, genetic improvement of peach, and extraction of health-promoting components. To effectively use the resource, we must have a measure of genetic diversity of P. davidiana and its population structure. LD (Linkage disequilibrium) provides information for association mapping underlying the phenotypic variation observed. Selective loci reveal adaptive evolution processes resulting from natural selection. A set of 190 genotypes from seven natural populations (SXTB, SIYQ, SXFX, NXXJ, SIJC, GSHT, GSHS) of P. davidiana collected from the range of P. davidiana in China was fingerprinted with 23 SSR markers, and analyzed with spatial structure, pairwise Fst (differentiation coefficient), PCA (principal coordinate analysis), estimation of groups of populations with STRUCTURE software, selective loci obtained from lnRH tested by standardization distribution and Grubbs. Our results demonstrate that population structure of four groups existed among populations through complementary analyses of the above mentioned methods; significant LD numbers from 22 to 129 between loci within unstructured populations were detected; there were five selective loci in all populations and two common selective loci for local natural selection between populations. We should conserve four populations among seven populations; these selective loci may provide information for disclosing adaption evolution and candidate genes according to selective loci and alleles; LDs inform how to use them for association analysis.