| The cultivation of rapeseed in China has a long history, the germplasm resources are quite rich. In recent years, about100new varieties were released each year as the breeding of hybrid rapeseed developed quickly. Therefore variety identification is quite crucial. Diversity analysis of rapeseed varieties also conducive to rape germplasm resources evaluation, utilization and protection, providing the basis for the continuous development of rapeseed genetic research. Here we utilize SSR and SNP to analyse the genetic diversity of winter rapeseed varieties of China in2011-2012and2012-2013. By applying the49SSR primers selected, the clustering of winter rapeseed varieties mentioned above was done. Also the genetic diversity was analysed. Several conclusions were made as follows:1. As the2011-2012cluster tree displaying, all of the172canola region test materials at the state level were divided into eight clusters with group B is devided into3subtribes. Another186canola region test materials at the state level were divided into five clusters with group A is devided into subtribe Al and A2. The varieties came from the same breeding unit or the same regions always are classified in one cluster. It is shown that the genetic relationship of varieties came from the same place are very close. Early maturity varieties and varieties from huanghuai region dispersed with high genetic diversity. The varieties from Yangtze river basin always clustered together, there were some genetic exchange among the group of the up, middle and lower reaches. Most of the materials clustered together as rapeseed materials from different regions, so the genetic diversity is not ideal. However, some rapeseed materials were specially grouped and showing large discreteness and special genetic diversity deserve to be protected and utilized.2. The genetic similarity coefficient showed a normal distribution among the national winter rape varieties. The number of group is less than others which lies in high similarity coefficient (0.8-0.9) and low similarity coefficient (0.4-0.5). On one hand, these varieties are rich in genetic diversity, and have wide genetic background. On the other hand, more rare species which are quite different from each others are still in need.3. The comparison of genetic similarity coefficient between various regions shows that all regions germplasm develop simultaneously, there is little difference between all regions about the genetic diversity. The genetic diversity of early maturity varieties is comparatively rich, followed with the middle and lower reaches of Yangtze river. The varieties from the upper reaches of Yangtze river and huanghuai region is worst. The genetic diversity of the total sample is much better than that of each regional varieties.4. From the research in the genetic diversity of national area test germplasm in2005-2013, we could get following conclusions. The total genetic similarity coefficient is high and the relationship is close in recent eight years. Overall, the entire genetic diversity coefficient was rising up, and had declined from2011.5. The comparison of SNP identify and SSR identifyClustering analysis of30regional testing varieties was identified by using20SSR primers pairs and15SNP markers. Through comparison between the SSR and SNP markers, we got the following conclusion:Both techniques can be successfully used to identified these materials. SNP marker polymorphism is better than SSR marker. Though clustering results is similar, there are also obviously different. To sum up, although the SNP markers is better than SSR markers in a certain extent, it is more conducive to the genetic fingerprint analysis of B.napus in the specific application when taking both to confirm each other. |
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