Population And Landscape Genetic Study Of Quercus Aquifolioides Rehd.EtWils. And Quercus Spinosa David Ex Franch.Based On Microsatellite Molecular Markers

Quercus aquifoliodes Rehd.Et Wils.and Quercus spinosa David ex Franch.are evergreen oak species belonging to Quercus section in Fagaceae,which are widely distributed in the high altitude range in southwestern China and adapt to harsh ecological environments.In this thesis,15 pairs of microsatellite molecular markers were used to conduct a population and landscape genetic study on 996 individuals from 60 Q.aquifolioides populations and 661 individuals from 46 Q.spinosa populations.Firstly,we studied the genetic structure and genetic diversity of Q.aquifolioides and Q.spinosa.The results showed that Q.aquifolioides and Q.spinosa differentiated into two distinct genetic lineages in their respective distribution areas: Q.aquifolioides differentiated into the Tibet lineage distributed in the eastern of Tibet and HDM-WSP lineage distributed in Himalaya-Hengduan Mountains-Western Sichuan Plateau;Q.spinosa differentiated into the West lineage distributed in the Hengduan Mountains region in western China and the East lineage distributed in the Qinling Mountains and eastern China.Secondly,the results showed that the the genetic diversity of HDM-WSP lineage is higher than that of Tibet lineage in Q.aquifolioides populations,and in Q.spinosa populations,the genetic diversity of East lineage is higher than that of West lineage based on Gen Al Ex.In addition,the genetic differentiation of Q.aquifolioides and Q.spinosa populations mainly exists within populations,and the genetic differentiation level of Q.spinosa populations are significantly higher than that of Q.aquifolioides.The results of gene flow analysis indicated that the historical gene flow occurred predominantly from Q.aquifolioides into Q.spinosa based on Migrate-n.Finally,multivariate statistical analysis and non-linear models showed different response mechanisms to environmental gradients in two lineages of Q.aquifolioides and Q.spinosa,respectively.In the Tibet lineage,geographic variables are the most important factors affecting genetic variation,while in the HDM-WSP lineage,climatic variables are the most important factors affecting genetic variation,precipitation seasonality(bio15)is the most important climatic variable affecting the genetic variation in HDM-WSP lineage.In the East lineage,geographic variables are the most important factors affecting genetic variation;while in the West lineage,climate variables are the most important factors affecting genetic variation,seasonal precipitation seasonality(bio15)and precipitation during the wet season(prec06)are the most important climatic variables affecting the genetic variation in West lineage.In this study,we studied the genetic characteristics(genetic structure,genetic diversity,etc.)of the populations of Q.aquifolioides and Q.spinosa,compared the genetic adaptation mechanisms of the two species within their respective distribution ranges.This study provides theoretical basic for a more in-depth study of the adaptation of two species and the formulation of corresponding conservation strategies,and provides a reference for the research on the population and landscape genetics of other forest species.