Abstract: The genetic diversity and genetic differentiation of 20 Pinus yunnanensis Franch. natural populations collected from the main distribution areas were studied by Simple Sequence Repeat (SSR) marker. The relationships among the genetic diversity and the main ecological factors, i.e., geographical, climatic and soil parameters, were analyzed. The genetic diversity parameters based on SSR loci for 20 natural populations were correlated with geographical, climatic and soil parameters. Those populations with rich genetic diversity existed in low latitude, low altitude, warm and moist environment. There was no significant relationship between matrices of genetic distance and matrices of geographical distance by Mantel test, which indicated that there was no evident sign of geographical isolation. But the ecological isolation was more obvious than geographical isolation. The genetic differentiation among populations may be influenced by geographical, climatic or soil factors. Climate factor had a main influence on genetic diversity of P. yunnanensis.

Key words: water stress, wheat, non-structural carbohydrates.