| This paper was firstly analyzed the genetic diversity, genetic structure and relationships of 18 Casuarina equisetifolia populations using AFLP. Based on the habitats of its distribution, possible reasons for genetic differentiation and genetic diversity of C. equisetifolia were discussed, and some strategies and suggestions for conservation and breeding were also given. The results were summarized as follows:(1) Total DNA were extracted from fresh branchlets using an improved method of CTAB, high quality DNA templates were isolated for AFLP analysis. Eight primer pairs were selected from a series of testing and clear fingerprintings of C. equisetifolia were obtained.(2) The results showed a high level of genetic diversity of C. equisetifolia at population level and species level. The average percentage of polymorphic loci (P), gene diversity(H) and Shannon information index (7) were 55.59%, 0.2113 and 0.3109, respectively, and species level were 1.7489, 0.4130 and 0.5972, respectively.The no. 5 population (provenance 18153,Ela Beach,Papua New Guinea) was highest in genetic diversity, may be Ela Beach of Papua New Guinea is a center of natural distribution of C. equisetifolia.(3) An analysis of POPGENE revealed that the total gene diversity was 0.4126, gene diversity within populations was 0.2113. The coefficient of genetic differentiation 0.4878 and low gene flow 0.2625 indicated high level of genetic differentiation among populations of C. equisetifoiia.An AMOVA analysis showed the variance components among populations and within populations were 45.7% (p<0.0002) and 54.3% (p<0.0002) ,respectively.(4) The genetic identity of 18 populations ranging from 0.5880 to 0.9339, and genetic distance from 0.0684 to 0.5310. At the coefficient value 0.34 , three major groupings could be recognized in the dendrogram. One group consisted of population 41 (CK,Dongshan,Fujian, China)only, second group comprised populations 5 (provenance 18153,Ela Beach,Papua New... |
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