Study On Genetic Diversity Of Syringa Pubescens

Syringa pubescens is one kind of beautiful ornamental plant, distributes in Chinese temperate region of Liaoning, Hebei, Henan, Shanxi, Shaanxi, Gansu and Qinghai province. It was cut away as shaw in afforestation, because its importance was not got the cognition in native distribution. For this reason the resources suffers to break seriously. 6 natural populations (Huashan in Shaanxi province, Hengshan in Shanxi province, Daheishan in Liaoning province and Songshan, Miaofengshan, Wulingshan in Beijing) were examined using two markers analysis of morphological traits and Amplified Fragment Length Polymorphism (AFLP). The genetic diversity of S. pubescens was evaluated in order to determine core germplasm and put forward efective methods for conservation of the genetic diversity. Main results were obtained as follows:(1) Morphological diversities among populations was analysed by characters such as apical bud, leaf, acorn and cupule. Analysis of variance for all characteristics were significantly diferent among populations and among individuals within population. The coefficient of variation (cv) was 14.63%-23.28%, maximal mean coefficient of variation (cv) of leaf width was 23.28%, the mean coefficient of variation (cv) of leaf stalk length was 22.55%, the mean coefficient of variation (cv) of leaf length was 21.79%, minimum mean coefficient of variation (cv) of cylindrical fireworks length was 14.63%, this indicates cylindrical fireworks length right away most highly in group inner stability. The mean phenotypic diferentiation coefficient (VST) shows that the variation among populations is higher than that within population. Indicating the Syringa pubescens having high genetic diversity among populations, and this is result since it has comparatively highly from selfing maturing rate.(2) Three populations located at Huashan in Shaanxi province, Hengshan in Shanxi province, and Songshan in Beijing, totally 90 individuals were selected and analyzed by amplifications using 6 pairs of AFLP primers, 28 bands produced each primer pair and 156 polymorphic locus were obtained. As for Syringa pubescens, Shannon's information index (I) is 0.3950 and Nei's gene diversity index (H) is 0.1906, genetic diferentiation coefficient among populations (Gst) is 0.5324, the mean of Gene flow estimated (Nm) was 0.2195. The variation among populations is 53.24 percent of the total variation. There has higher genetic diversity between populations. According to the UPGMA cluster analysis, the genetic distance among Syringa pubescens populations becomed larger with the increasing of geographical distance.(3)Strategy for conservations ampling of core collection through analysis on genetic diversity of Syringa pubescens and study on population genetic structure can be obtained accordingly. The sampling strategy for conservation in original place: 6 populations were selected as conservation object. The sampling strategy for conservation, ex situ: sampling 6 populations with 30 sampled individuals for each population, the smallest plant space of above 30 m among each individual and total conservation number of 180 individuals.In summary, the quantitive criteria for evaluating genetic diversity and sampling stategy for genetic resources conservation and utilization of Syringa pubescens had been provided, and the results could been used to guide genetic resources collection, conservation and elite breed selection of lilac. This study was significative for genetic diversity research and conservation of Syringa.