Genetic Variation Of Cryptomeria Japonica Var.sinensis From Different Geographic Provenance And Its Prediction Of Potential Suitable Areas

Cryptomeria japonica var.sinensis(also called Liushan)is a unique relic plant in East Asia,which widely distributed in southern China.It is an excellent afforestation and greening tree species with high economic value.In 1950s to 1960s,the plantations of Liushan were largely developed in southern China with stretches thousands of kilometers from the coast of Fujian to the west of Sichuan.Later,Cunninghamia lanceolata has gradually occupied the major position of the plantation in southern China,and has stopped the plantation development of Liushan.Due to the long-term ignorance of protection and management,the genetic resources of Liushan in China have been seriously damaged.Therefore,the genetic background and source of plantations in many places were unclear,restricting the current research of genetic breeding and the industrial revitalization.Our aim is to protect the genetic resource and to develop plantations of Liushan.In this study,the methods of morphology,population genetics and ecology were comprehensively used to analyze the genetic variation of different geographical provenances,evaluate the genetic diversity of plantation,clarify the genetic background and source of some plantation populations,and analyze the distribution patterns and potential suitable area of Liushan under the climate change.The research results are provided a great significance for the protection of Liushan genetic resources and genetic breeding in China.The main results are as follows.(1)The phenotypic variation of Liushan from different geographical provenances was rich.The genetic variation analysis of 6 geographical provenances showed that the phenotypic variation of Liushan geographical provenances was rich,and the genetic variation among provenances were greater than that within provenances,among which the coefficient of variation of leaf area was the largest(CV.=40.71%)and the leaf length was the most stable(CV.=25.45%).The cluster analysis results further showed that the 6 geographical provenances could divided into three category,namely Fujian category,including XP and NP;The provenances of Zhejiang XTMS,Hunan LT and Sichuan HY showed close genetic relationship and were clustered into the second category;Yunnan provenance MGS was divided into a category with unique phenotype and the largest leaf area,which deserves further attention.(2)The plantation population of Liushan have the characteristics of medium genetic diversity and obvious genetic differentiation among populations.The total genetic diversity(Ht)of the plantation population of Liushan was 0.576,which was at a medium level(He=0.512,Ho=0.502)based on SSR molecular.The genetic diversity of MGS population was the highest(He=0.492,Ho=0.612),while YA population was the lowest(He=0.483,Ho=0.391).There was high genetic differentiation among populations(Fst=0.093).The result of genetic structure analysis divided 13 plantation of Liushan species into three gene pools,Fujian populations(NP,NP1)and Sichuan YA;Hunan populations(LT,HS,MS)and Zhejiang population(XTMS,DTMS)and Fujian XP;Sichuan population(HY,ZGS,LYS)and Yunnan population(MGS).These results showed that the plantation of Liushan was basically developed from local provenances,and the source of YA population in Sichuan maybe introduced from Fujian.(3)The central distribution area of Liushan was southeast of China.The simulation results of species distribution was good(AUC=0.947)base on MaxEnt.The dominant environmental variables were precipitation and temperature,affecting the distribution of Liushan.At present,Liushan was mainly distributed in southeast and central south China,such as Fujian,Zhejiang,Jiangxi and Hunan province.Compared the LGM(0.589 × 104 km2),the distribution area were shirk consistently,and it would be further reduced in the future.Since the LGM centroid of the suitable distribution area has migrated to the southeast with climate warming and to the West or North under future climate change,among which the migration distance was the farthest under the RCP 4.5 climate scenario.(4)Genetic resources protection and breeding strategy of Liushan.In order to greatly preserve the existing genetic resources,the germplasm nurseries or seed orchards would be established regionally,including the East(Fujian),Central(Hunan)and West(Sichuan and Yunnan)of China.The current genetic resources of Liushan were sufficient utilized and the good varieties of Liushan were bred and popularized,promoting the productivity of plantation of Liushan.It worth to focus that Yunnan provenance MGS with unique phenotype.