| Summary: | 博士 === 國立中興大學 === 生命科學系 === 92 === Taiwan Fir is a glacial relic conifer species endemic to Taiwan. It is distributed from 2400 m to 3800 m in altitude and from 230 N to 24.80 N in latitude. Its distribution is more or less continuous from Nanhudashan in the north to Beinanchushan in the south. Its neighboring species usually include species of Yushania, Juniperus, and Tsuga. The reproduction of the species is generally in cycles and its habitats experience forest fire periodically. The genetic variation of the species was investigated in the present study using ISSR fingerprinting method. The result indicated that most of the neighboring mountain systems have closer genetic relationships. Cluster analysis and principal coordinates analysis revealed close relationships between neighboring Nanhudashan and Shiunmagiunshan; Guanshan and Shianyanshan; and Hohuanshan, Shieshan, Ganzuowanshan and Chilaishan. The genetic differentiation among populations is significant (Gst = 0.3237) and there is gene flow among populations (Nm = 1.0445). The population differentiation may be resulted from specific mountain landscape and isolation by distance. The gene flow is resulted from wind transportation of pollens and seeds. The population genetic analysis revealed that the species has high genetic variation, with the variation source mainly within populations. The northern and central portions of the Central Mountain Range from Shiunmagiunshan to Ganzuowanshan have high genetic diversity, with Shiunmagiunshan and Hohuanshan the highest diversity. The total diversity index (H) of the species was 0.3641. The result of phylogenetic study using 4CL sequence data was unable to reveal the relationship among populations. The 4CL sequences of endosperm samples were also unable to resolve the relationship among populations. The result using 4CL and NAD5 sequences of Taiwan Fir and other species of Pinaceae from GenBank indicated that the relationship among species generally is congruent with the result of a previous study. The study resolved the relationship among genera. However, both Bayesian Inference and Maximum parsimony analyses failed to clarify the relationship among species of the genus Abies. The comparison between methods of BI and MP indicated that BI has good resolution near terminal of evolution tree and generally has higher support for each clade. However, in the NAD5 analysis using BI it has weak resolution near the root of the tree. Population genetic analysis indicated that the Hotspot of the conservation biology of Taiwan Fir is located around Shiunmagiunshan and Hohuanshan. The conservation of these populations is critically important. The global climatic change may be a stress for Taiwan Fir and it is suggested that long term population genetic data should be established for conservation consideration. Some parameters of the genetic structure of Taiwan Fir have been provided in the present study. The most important factor in determining genetic diversity is the evolution history of the species concerned. Populations that experienced longer evolutionary history generally have greater genetic diversity and are more important in conservation. Therefore, populations of Beelushan, Shieshan, Yushan, and Shianyanshan should also be emphasized in conservation policy.
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