Abstract: Seeds were collected from 30 trees selected from each of the 3 natural populations of Syringa oblata Lindl. located respectively in Daheishan mountain in Inner Mongolia Autonomous Region, Beipiao in Liaoning Province and Wulaofeng in Shanxi Province. 72 wild accessions of the collections were used in this study. Seedswere germinated and a bulk sample of 20 leaves was collected from each family for molecular marker analysis. Eight EcoRI-MseⅠ AFLP primer combinations revealed 864 legible bands of which 187 were polymorphic markers. Nei's genetic diversitywas 0.2287, Shannon's information index was 0.3464, genetic diversity at species level was 0.3522, observed heterozygosity was 0.2287 within population and 0.1235 among populations, coefficient of genetic differentiation was 0.3508 and the average gene flow estimated from Gst was 0.9253. The results of AMOVA indicated that the variance component of among populations contributes 51.53% to the total genetic variance. UPGMA cluster analysis based on Nei's genetic disitance indicated that genetic distances were closely related to corresponding geographic distances among populations. The results also indicated that genetic differentiation among populations was large, mainly attributable to geographic isolation due to the discontinuous distribution of the species and high rate of selfing. Conservation strategy for the species should be therefore emphasized on conserving as many as possible the existing populations
considering the current conditions of severe population fragmentation and losses.

Key words: Syringa oblata, Natural population, Amplified Fragment Length Polymorphism (AFLP), Genetic diversity