The Genetic Diversity Of Tobacco Varieties Certificated In China Based On Fluorescent SSR And Capillary Electrophoresis

Tobacco(Nicotiana tabacum) is an important economic crop, it has formed different variety resources in China through the natural and artificial selection and the continuous introduction from abroad. Since the year 1986 to 2010, 91 tobacco varieties have been certificated by China's State Tobacco Variety Approval Committee. The promotion and application of these tobacco varieties has played a positive role in tobacco production in China. In this study, a high throughput detection system for tobacco varieties SSR markers based on the fluorescence-based SSR marker and capillary electrophoresis technique was established. The system was then used to study the genetic diversity and kinship of the main tobacco varieties certificated in China. The order is to provide a scientific basis for parent selection and utilization of favorable genes in tobacco breeding. The main results are as follows:1. The detection technique based on fluorescence-based SSR marker and capillary electrophoresis was used. By adjusting the amount of components and cycling conditions, we established a PCR amplification and detection system that fitted for the Beckman CEQ8000 automated genetic analysis system. Compared to the polyacrylamide gel electrophoresis, fluorescence detection technique of capillary electrophoresis overcame the shortage of silver staining and had merits of simple, reliable and high-throughput. Meanwhile, the strategy of building low-cost and high-throughput multiple PCR system in microsatellite fluorescentmark was discussed.2. 36 pairs of SSR primers were selected to amplify the 71 tobacco varieties. The PCR reactions generated 2437 DNA bands, of which 205 were polymorphic bands. Each pair of primer was able to amplify 2~15 DNA bands on the average; the average polymorphism rate was 8.4%. The results showed the high efficiency of the SSR technology in genetic diversity of tobacco germplasm resources.3. UPGMA cluster based on the Dice genetic similarity coefficient was analysed. The results showed, when the clustering threshold was 0.35, the flue-cured tobacco and burley tobacco were divided respectively into different groups. The flue-cured tobacco group were further divided into 10 sub-groups, the burley tobacco group were divided into 3 sub-groups. The results also showed that 13 flue-cured tobacco varieties introduced from abroad were all distributed in the domestic tobacco groups, the tobacco varieties breeded by the same place due to their closer geographical location and higher genetic similarity were gathered in the same group or sub-group.4. The research analyzed the genetic diversity between the 63 flue-cured tobacco varieties and 8 burley tobacco varieties, the results could provide the scientific basis of the parent selection and utilization of favorable genes in the tobacco breeding work.