Genetic Diversity Analysis And Fingerprinting Construction Of Core Parents In Rapeseed(Brassica Napus L.)

China is the largest country in rapeseed production, and also the first country which successfully utilizes rapeseed heterosis in large-scale over the world. Hybrid of rapeseed is warmly received by seed companies and farmers due to its high yield, stress resistance and wide adaptability.With continuous progress of the commercial market, because of putting impure or fake materials in the commodities or producing hybrid seed through improper means by some illegal operators, it may damage the interests of the farmers, entrepreneurs and breeders.Therefore, it urgently needs to establish the technical system in order to protect hybrid variety and identify the reality of parents and purity of hybrid seeds, as a result it will provide technical support for intellectual property of hybrids and protecting legal rights of farmers.SSR markers have the character of co-dominant, good stability, simple inheritance and being capble of detecting multiple alleles, so SSR markers are widely used for purity and reality identification in many crop varieties, such as corn, rice. Gentic diversity of120materials in rapeseed(Brassica napus L.) was evaluated with SSR molecular markers so as to build the the SSR-DNA fingerprinting of core parent lines. Meanwhile it can provide a reliable reference for identifying the reality of parents and purity of Fl hybrid seeds. The main results were as follows:1. Six genetically different materials (two male sterile lines, two restorer lines and two conventional lines) had been selected from120materials for screening markers from1938pairs of SSR primers in our laboratory.543pairs of polymorphic primers were obtained, and then173pairs of SSR primers with clear band pattern, stable and high polymorphisms were chosed for subsequent analysis.2. All the120materials were analyzed by these173pairs of SSR primers, total646bands were amplified, of which512bands exhibited polymorphic, and the polymorphic rate was80%. Each pair of SSR primers can amplify2-8polymorphic bands with the averageof3.8. The value of PIC is range from0.05to0.92with the average of0.61.3.512polymorphic loci were analyzed by UMPGMA cluster analysis based on the genetic similarity threshold of0.61, and all the120material could be divided into two groups, which designated A and B. A total of100materials in group A could be divided into four subgroups with the similarity coefficient being0.69. Of them, most CMS lines were gathered in the subgroup I and subgroup Ⅱ, which indicated the genetic variation was relatively small. While the49restorer lines were distributed in five subgroups, which indicated that these materials were significantly genetic difference.4. According to the result of PCR, the polymorphic loci amplified by173pairs of primers with no band were designated as’0’, and which had the band were designated as ’1’. Using this information, the standard digital fingerprints of32core parents were constructed. Moreover, the preliminary computer database of core parents fingerprints was created for quickly searching for any parents.