Genetic Structure Of Chinses Pine (Pinus Tabuliformis) Plantations In Beijing And Differences With Nature Populations In Shanxi

There are certain ecological restrictions on the adaptability and normal growth of different geographical populations within tree species,and improper allocation of seeds across ecological regions can lead to the decrease in stability and productivity of stand.The adaptive evolution of exotic germplasm to the natural habitat and cultivation measures has an important influence on its sustainable utilization value.In the 1950 s and 1980 s,large-scale artificial afforestation was carried out in Beijing.Chinese pine(Pinus tabuliformis Carr.)was among the main planting species and its provenance mainly came from the Shanxi province,the central distribution area of Chinese pine.There are obvious differences in growth and adaptability between plantations.However,are the differences related to provenances or site effect,how about the differences and similarities of genetic structure between plantations with the ancient populations in royal garden of Beijing,and geographic sources in Shanxi,and whether plantation sites would change the genetic structure of exotic provenances.To reveal and clarify those problems would be helpful for understanding the effects of evolution and domestication on exotic provenances and the cultivation and management of plantations of Chinese pine in Beijing.In this study,8 plantations of Chinese pine planted in Beijing last century and 3 ancient plantations in royal gardens were sampled.7 pairs of nuclear genomic EST-SSR primers and population genetic software were used to analyze the genetic structure features and differences of the checked population,and compared with the genetic structure of the 5 mountains populations in Shanxi Province.The main results are as follows:(1)All of the 8 plantations showed deviation from Hardy-Weinberg's Equilibrium Law,which indicating that 8 populations were affected by the fitness selection,5 populations showed excess heterozygosity,and 3 insufficient heterozygosity;the expected heterozygosity of the various populations was generally greater than that of the royal populations and higher genetic diversity;the main genetic variation source from within the population,and relative higher genetic variation among populations than the populations in Shanxi and the royal populations in Beijing.(2)The frequencies of allele markers showed a certain trend of difference among population types.The frequencies of some allele markers were higher in plantations and royal populations,but lower populations in Shanxi.The frequency of individual allele markers was higher in plantations and lower in royal populations in Beijing.(3)All tested populations could be divided into 3 main groups,among which the royal populations as: GS1,GS2 and GS3 are classes in the one subclass of the first category(class ?),and other Beijing plantations(except JLS)have the same clustered in the first category(class ?),while populations in Shanxi were all in the second category(class ?),showing the similarities and differences between the different sources of populations.(4)Although the EST-SSR markers of Chinese pine genome could not accurately infer the provenance of tested plantations,the relative relationship between different populations might be determined.However,the selection effect of site environment and domestication effect of plantation cultivation would lead to the change of population genetic structure,and the EST-SSR marker on gene coding region would be limited for source tracing of populations.The study provided corresponding basis information for the evaluation,cultivation and provenance management of Chinese pine plantations in Beijing,and have certain reference value for relative studies of other tree species.