Study On Phylogenetic Relationships Of Ponkan In China

China is the origin and genetic variation center of Citrus. The collection, conservation, classification, identification and utilization of germplasm is very important to maintain the development of Citrus industry. Nowadays, the classification of Citrus had been made great progress and the taxonomy system is come into being gradually. But it is still always confused in many varieties and cultivars. Such as ponkan(Critrus reticulata Blanco), one of the superior mandarins(C. reticulata Blanco) in citrus and planted widely in china. However, few reports on the phylogenetic relationships of ponkan having been published. In this study, AFLP technique was used to perform research 21 ponkan materials and its relatives in phylogenetic relationships. The main results were as follows:1. 104 EcoRI/MseI primer combinations were tested and 8 of them with better performance were selected for further research. A subset of 8 primer combinations were used for study the phylogenetic relationships of 21 ponkan and its relatives and generated 116 polymorphic bands out of 469 total bands. Each primer combinations obtained 58.6 clear bands. The polymorphic rate of AFLP markers was 24.7% .2. All of the 17 varieties and cultivars of ponkan can be clustered into one group. And the similar coefficient amony them are all above 0.86. It is indicated that ponkan has close genetic relationship and narrow genetic background. Ponkan has very small genetic variation in the long process of evolution. UPGMA cluster analysis based on AFLP fingerprinting showed that, Jian'gan tangerine and Red tangerine have high similality(the similar coefficient is 0.84) and can be clustered into one group. Compared with Bendizao tangerine and ponkan, The Jian'gan tangerine has closer genetic relationship with Red tangerine.3. 'Huagan No.2', a new superior ponkan cultivar, which was examined and approved recently. But its origin and genetic background is not clear. In this research 'Huagan No.2' has closest relationship with Changyuan ponkan, two of them can be clustered into one group within ponkan. 'Huagan No.2' probably derived from the variation of Changyuan ponkan. 'Huagan No.2' also produced another seedless variation, there are some differences between 'Huagan No.2' and its seedless variation. Furthermore, 'Huagan No.2' and its seedless variation have comparative far distance showed in the clustering graph. The probable reason is that, all varieties of ponkan have closest genetic...