Analysis of population genetic structure of Puccinia striiformis f. sp. tritici from central Gansu and the surrounding areas Genetic diversity of Gaeumannomyces graminis var.tritici populations in Huang-Huai Winter Wheat Production Region of China Population Genetic Structure in Apricot (Armeniaca Mill.) Revealed by Fluorescent-AFLP Markers Population Genetic Structure in Apricot (Armeniaca Mill.) Revealed by Fluorescent-AFLP Markers Analysis of population genetic structure of Puccinia striiformis f. sp. tritici in Shaanxi Province, China