| Based on the analysis of genetic diversity and genetic structure of Pinus yunnanensis high-quality timber,the sample strategies of ex-situ conservation and in-situ conservationof P.yunnanensis high-quality timber were researched,respectively.The genetic diversity and genetic structure of P.yunnanensis high-quality timber were analyzed through eighteen phenotypic characters and SRAP markers in seven hundred and eighty P.yunnanensis samples fromtwenty-six natural populations of the whole distribution area.Thirty samples were selected from each population according to the good shape of the trunk.Twenty-sixnatural populations in the whole distribution region of P.yunnanensiswere selecteddepending on the provenance division and the geographical distribution of P.yunnanensis.The key problem in the conservation of P.yunnanensis germplasm resources was expected to solve by this research.The research results could be provided the method basis of sample strategy and the source of germplasm materialsfor the protection and utilization of P.yunnanensis germplasm resources.The results were as follows:(1)Study on genetic diversity and genetic structure of P.yunnanensis high-quality timberThe genetic diversity and genetic structure of P.yunnanensis high-quality timber populations were researchedthrough the phenotype values of 18 quantitative traits and SRAP markers data.The results of phenotypic genetic diversity research on P.yunnanensis population showed that the percentage of variance component in-population(54.2288%)was greater than that of inter-population(21.4557%),the phenotypic variance differentiation coefficient and phenotypic frequency differentiation coefficient of inter-population were 29.0167%and8.5500%,respectively.The inter-population genetic differentiation coefficient was 0.1013 and the gene flow was 4.4357 through SRAP markers analysis in this research.The result of variance component analysis of SRAP markers was similar to those of phenotypic traits,the percentage of variance component in-population(87%)was greater than that of inter-population(13%).It was discovered that the genetic diversity of P.yunnanensis was at medium level among the pinus species by the SRAP molecular markers and phenotypic genetic diversity research on P.yunnanensis population.The polymorphisms were observed both in-population and inter-populationof P.yunnanensis through the phenotypic genetic diversity research and the SRAP markers analysis on P.yunnanensis population.Phenotypic differentiation estimation and SRAP markers genetic differentiation analysis showed that the variation of P.yunnanensis mainly existed in the population.The significant differences were observed among the twenty-six populations by eighteen phenotypic traits.Multiple comparisons showed that the phenotypic genetic diversity of the nine populations in Shuangjiang of Yunnan,Longling of Yunnan,Maguan of Yunnan,Qujing of Yunnan,Yongren of Yunnan,Ceheng of Guizhou,Shuicheng of Guizhou,Lijiang of Yunnan and Chayu of Xizang were more abundant than that of the remaining seventeen populations.Among the twenty-six populations,the genetic diversity of the three populations in Miyi of Sichuan,Chayu of Xizang and Xinping of Yunnan were more abundant than that of the remaining twenty-three populations by the SRAP molecular markersresearch on P.yunnanensis population.This study clarified that the genetic variation of P.yunnanensis mainly existed in populationand the specific populations with relatively rich genetic diversity were selected,which provided theoretical basis and data support for the determination of the sampling proportion in the group of germplasm preservation bank construction strategyand the determination of the preferred conservation populations of in-situ preservation strategy.(2)Study on construction strategy of germplasm preservation bank of P.yunnanensis high-quality timberThe germplasm subsets of different sampling proportions(10%,20%,30%and 40%)were constructed based on three types data of the phenotype values,the SRAP molecular markers information and the integrate phenotype values and SRAP molecular markers information of P.yunnanensis,respectively.Thus,the strategy of establishing germplasm bank(ex-situ conservation)of P.yunnanensis high-quality timberwas studied.The quantitative traitsdetection and evaluation results of the germplasm subsets ofdifferent sampling proportions based on phenotype values and Euclidean distance showed that the phenotypic diversity index average of 20%sampling proportion germplasm subset was significantly greater than that of original germplasm set,furthermore,when the sample proportion was 20%,the change rate of variable coefficient and variance difference percentage were the largest of the four sample proportions,the range coincidence rate and phenotypic retention ratio were relatively large and the mean difference percentage was relatively small of the four sample proportions.To sum up,the 20%sample proportion was better than the other three sample proportions when the germplasm bankwas established based on phenotype values and Euclidean distance.The quality traits detection and evaluation results of the germplasm subsets ofdifferent sampling proportions based on SRAP molecular markers information and Nei's distance showed that the sampling proportion of 40%and 30%were better than the other two sampling proportions from mean t-test,variance F-test and correlation coefficient comparison of germplasm subsets.At the same time,considering the workload and cost of germplasm resource preservation,30%was the appropriate sampling proportion when the germplasm bankwas constructed based on SRAP molecular markers information and Nei's distance.The quantitative traitsdetection and evaluation results of the germplasm subsets ofdifferent sampling proportions based on integrate phenotype values and SRAP molecular markers information and mixturegenetic distance showed that the sampling proportion of 30%was better than the other three sampling proportions,meanwhile,the quality traits detection and evaluation results of these showed that the sampling proportion of 40%and 30%were better than the other two sampling proportions from mean t-test,variance F-test and correlation coefficient comparison of germplasm subsets.Therefore,based on the evaluation results of the two types of trait parameters,the sampling proportion of 30%was better than the other three proportions when the germplasm bankwas constructed based on integrate phenotype values and SRAP molecular markers information and mixturegenetic distance.Study on the sampling strategy of germplasm bank construction(ex-situ conservation)of P.yunnanensis high-quality timber,it was found that the sampling strategy of using integrate phenotype values and SRAP molecular markers information of P.yunnanensisand using mixturegenetic distance was better than that of using phenotype values or molecular marker data alone and using their respective appropriate genetic distance,for the variation of samples in the germplasm subset was larger than that of the other two germplasm subsets,the meandifference test and frequency distribution test of the germplasm subset were more sensitive than that of the other two germplasm subsets,the correlation between the germplasm subset and the originalgermplasm set was better than that of the other two germplasm subsets.Finally,it was found that the appropriate sampling strategy to construct P.yunnanensis high-quality timber germplasm bank was that adoptingintegrate phenotype values and molecular marker data,grouping by samples's geographical sources,using mixturegenetic distance and unweighted average clustering method,sampling proportion of 30%and improved minimum distance stepwise sampling method.The germplasm bank containing two hundred and thirty-four samples was constructedin accordance with the appropriate sampling strategy,which could be used as a representative subset of the overall resources of P.yunnanensis high-quality timber and as the overall samples for ex-situ conservation of P.yunnanensis high-quality timber germplasm resources.(3)Study on sampling strategy of in-situ conservationof P.yunnanensis high-quality timberStudy on the sampling strategy of in-situ conservationof P.yunnanensis high-quality timber,the capture curve and model of genetic markers were established by polynomial regression statistical analysis technology according to the molecular marker information of SRAP.With curve and model analysis,it was showed that the samples's representativeness for the overall resources of P.yunnanensis high-quality timber could reach more than 95%,when10-12 populations and 20-24 individual each populationwere sampled based on the percentage of polymorphic loci.Hence,the sample size strategy for in-situ preservation of P.yunnanensis high-quality timber germplasm resourceswas finally determined as follows:twelve populations samples,twenty-four individual samples within each populationand an appropriate storage area of five hm~2for each population.For making the in-situ conservation populations have been more targeted and practical,under the premise of the number of population samples was ensured,the determination of in-situ conserving population was no longer random but the genetic diversity and geographic distribution of the population were taken into,the Mmix(I)of Shannon diversity index mixed evaluation parameter and the Dmix of mixed genetic distancewere used to analyze and evaluate the genetic diversity of twenty-six populations,and eventually the twelvepopulations of Xinping of Yunnan,Miyi of Sichuan,Chayu of Xizang,Xianggelila of Yunnan,Fugong of Yunnan,Longling of Yunnan,Lijiang of Yunnan,Leye(2)of Guangxi,Shuangjiang(1)of Yunnan,Shuicheng of Guizhou,Yongren of Yunnan and Ceheng of Guizhou could be as the population samples in-situ conservation of P.yunnanensis high-quality timber germplasm resources.In conclusion,in-situ preservation strategy of P.yunnanensis high-quality timber was proposed,it not only contained sample size strategy but also contained the information of priority preservation groups,therefore,the strategy could make the in-situ preservation of P.yunnanensis high-quality timber germplasm resources have been more targeted and practical,the purpose and requirement of the permanent preservation of P.yunnanensis high-quality timber germplasm resources could be realized by the in-situ preservation strategy. |
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