| Summary: | 碩士 === 中國醫藥大學 === 醫學研究所 === 93 === Concerning the evolution of species, the mutual hybridization among the biological species often causes the difference on the hereditary characteristic. Utilizing the convenient and stabile ISSR （inter simple sequence repeat）molecular maker can analyse hereditary similarity and make the setting-up of ISSR DNA fingerprint database among the biological species. In this study, we utilize Sweet Orange (C. sinensis [L.] Osbeck) for the experiment, the twenty cultivars of Sweet Orange can be divided into four groups, including Common Orange、Navel Orange、Blood Orange and Acidless Orange. Objectives were to assess genetic similarity among the cultivars. There were 51 polymorphic bands produced by 8 selected ISSR primers. The result of ISSR suggested that among the dinucleotides motifs, the poly(AC)n motif was more abundant and gave the largest number of polymorphism. Genetic similarity among the twenty cultivars was detected from 17% to 72% on ISSR marker basis. The cluster analysis of genetic similarity by UPGMA (Unweighted Pair-group Mean Arithmetic) revealed that four major groups could be recognized. The most interesting is the 4th group which includes most kinds can be observed that are mainly divied from two groups, one includes the Common Orange with fewer seeds and lower acidity and the other one includes the Navel Orange and Common Orange with high acidity. Among the Navel Orange, there is the highest similarity between cv. Frost and cv. Washington. Hereditary similarity value is up to 72% . Thus, it can be seen the quick and reliable molecular tool is useful in selecting the best parents and obtaining new combinations.
|
|---|
