| As the major forestry pest insects in China,Dendrolimus included Dendrolimus punctatus punctatus Walker.D.Punctatus tabulaeformis Tsai et Liu.D.punctatus spectabilis Butler.D.superans Butler.D.houi Lajonquiere and D.kikuchii Matsumura. During sequential outbreaks,economical damage can be so extensive for forest appears to be burned and unable to withstand such a long period of defoliation.We assess gene diversity and genetic structure among four species of Dendrolimus spp,among geographical populations of D.punctatus Walker and among sub-populations of D. punctatus tabulaeformis Tsai et Liu using morphological diversities,allozyme,RAPD and SSR,which provide-a powerful tool for investigation of genetic variation.The influence of ecological factors on the genetic diversity and morphological diversity is also discussed by the correlation analysis.(1)Genetic diversities and morphological diversities among D.punctatus punctatus Walker.D.superans Butler.D.houi Lajonquiere and D.kikuchii Matsumura:Morphological diversities among four species of Dendrolimus spp.were analyzed including pupae weight,pupae length,female weight,female wing length,female length, male weight,male wing length and male length.Analysis of variance for all characteristics was significantly different among species.Coefficient of variation of morphological traits showed that pupae weight is significantly higher than other traits.Pupae length,female weight and female wing length were the main traits account for the phenotypic variations according to the Principal Component Analysis(PCA)and disciminte analysis.Basing on the UPGMA cluster,four species of Dendrolimus could be divided into two groups:the first branch in the dendrogram included D.punctatus punctatus Walker and D.superans Butler,and D.houi Lajonquiere and D.kikuchii Matsumura were grouped together into second branch.The correlations between the phenotypic traits and ecological and geographic factors are significant.There was no significant relationship between the Euclidean distance and geographic distance among species of Dendrolimus spp.During allozyme method on the sampled species,a total of 12 presumed loci and 22 alleles were scored in this study,which 6 loci were polymorphic.At population level,the mean number of alleles per locus(A)was 1.2708,the Percentage of polymorphic loci(P) was 25.00%,and the mean expected heterozygosity per locus(He)was 0.0828.At species level,A=1.8333,P=50.00%,He=0.2323.So,the genetic diversity at species level was rather high than that at populations level.A UPGMA dendrogram was generated based on Nei's genetic distance showed 4 species of Dendrolimus were clustered into three groups: the first branch in the dendrogram included D.punctatus punctatus Walker and D. superans Butler,and D.houi Lajonquiere and D.kikuchii Matsumura became the second and the third branch independently.The correlations between the genetic data and ecological factors are not significant except for Shannon information index and altitude. There was no significant relationship between the genetic distance and geographic distance.(2)Genetic diversities among 6 geographical populations of D.punctatus Walker:At population level,the percentage of polymorphic loci(P)was 25.19%,the mean number of alleles per locus(A)was 1.252,Ae=1.069,the mean Shannon's information index(I)was 0.090.For the species level,P=82.95%,A=1.830,Ae=1.398 in RAPD analysis method.The coefficient of genetic differentiation between populations based on Shannon information index was 0.7490,based on Nei's genetic diversity was 0.7780, which revealed a very high level of genetic differentiation among populations.The number of migrants per generation among populations(Nm)was 0.168 based on Shannon information index,Nm was 0.143 based on Nei's genetic diversity,which revealed a very low gene flow among populations.Shannon information index and Nei's genetic diversity all showed that there was highest genetic diversity in population of D.punctatus punctatus Walker of YJM,the lowest genetic diversity in population of D.punctatus spectabilis Butler of JZC.Three populations of D.punctatus punctatus Walker and three populations of D.punctatus spectabilis Butler were clustered into one branch independently by using Nei's unbiased genetic distances.The correlations between the genetic index and ecological and geographic factors are significant.There was no significant relationship between the genetic distance and geographic distance among populations.In allozyme method,a total of 10 presumed loci and 15 alleles resolved were scored in this study,which 3 loci were polymorphic.At population level,the mean number of alleles per locus(A)was 1.233,the percentage of polymorphic loci(P)was 21.67%,and the mean expected heterozygosity per locus(He)was 0.067.At species level,A=1.500, P=30.00%,He=0.089.So,the genetic diversity at species level was rather high than that at populations level.From the summary of F-statistics at polymorphic loci of 6 populations, we could found the Fst was 0.265,which mean there show high genetic diversity among populations.The number of migrants per generation among populations(Nm),based on Fst calculations,was 0.692,suggesting the occurrence of rather low gene flow among populations.A UPGMA dendrogram was generated showed 6 populations of D.punctatus Walker were clustered into two groups:the first branch in the dendrogram included three populations of D.punctatus spectabilis Butler,and the remaining three populations of D. punctatus punctatus Walker were grouped together into second branch.The correlations between the genetic data and ecological factors are not significant.There was no significant relationship between the genetic distance and geographic distance among populations,the same to the RAPD data.(3)Genetic diversities among 5 sub-populations of D.punctatus tabulaeformis Tsai et Liu:Polymorphic bands were produced using 8 primers in SSR analysis method.The percentage ofpolymorphic loci(P)was 80.00%,the mean number of alleles per locus(A) was 2.6250,and the mean expected heterozygosity per locus(He)was 0.3765.For the species level,P=87.50%,A=3.1250,He=0.4747.From the summary of F-statistics at polymorphic loci of 5 sub-populations,we could found the Fst was 0.2159,which mean there show high genetic diversity among sub-populations.There were the highest genetic diversity in sub-population of pure Pinus tabulaeformis Carr,the lowest genetic diversity in sub-population of the artificial mixed forest of P.tabulaeformis Carr and Larix principis-rupprechtii Mayr.The number of migrants per generation among populations (Nm)was 0.9081,suggesting the occurrence of rather low gene flow among sub-populations.A UPGMA dendrogram based on Nei's genetic distance showed 5 sub-populations of D.punctatus tabulaeformis Tsai et Liu were clustered into two groups: the first branch in the dendrogram included pop1 and pop2,and the remaining three sub-populations were grouped together into second branch.The genetic index has positive relationship with ecological factors but not significant.Stand type,slope,aspect and altitude were the main traits account for the genetic diversities according to the PCA.
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