| Genetic diversity of 9 Tibet populations with 8 control groups was studied by microsatellite method (SSR)and amplified fragment length polymorphism(AFLP) in order to evaluate the genetic diversity, quantity and distribution of germplasm resources of the Tibet wild Elymus L. on molecular level and provide a scientific basis for the protection and utilization while comparing the effectiveness of the two molecular marker technique in the evaluation of the genetic diversity of Elymus L.. The main results were as follows:1.Based on the previous research, through optimizing the SSR reaction system and reaction procedure of Elymus L. the optimization reaction system and reaction procedure system for SSR analysis was successfully established and it also proved that the general availability of relative genus microsatellite primers.2.Based on the previous research on AFLP reaction system and reaction procedure, the AFLP silver-staining analysis system suitable for genomic DNA of Elymus L.was established for the first time.3. SSR marker: 32 primer pairs were used for polymorphism selection, 14 primer pairs obtained amplified products, 8 primer pairs produced specifically polymorphism products; using those 8 primer pairs to analyse the 17 materials by microsatellite method ,a total of 69 sites were observed,among them 59 sites showed polymorphism sites. The average number of polymorphism site produced by each primer was 7.4. Genetic identity ranged from 0.273 to 0.900 among the 9 populations with a high variation range, which showed that the Tibet germplasm resource of wild Elymus.L had a high genetic diversity. The result of cluster analysis with UPGMA showed that when genetic identity is 0.59, the17 populations can be dividing into 5 groups, which basically showed the genetic relationship amang 9 populations and also proved that SSR marker could be used for the analysis of genetic diversity of wild Elymus L.4. AFLP marker: 16 primer combinations were used for polymorphism selection and 3 primer combinations produced specifically polymorphism products. A total of 232 sites were observed, among them 206 sites are polymorphism sites, the average number of polymorphism site produced by each primer combination was 68.67. Genetic identity ranged from 0.284 to 0.955 among the 17 populations. The cluster analysis with UPGMA showed that when genetic identity is 0.59, the 17 populations could be divided into 4 groups.5. Comparison of SSR marker with AFLP marker: The ratio of polymorphic sites obtained by SSR marker was 85.5%, more than 88.79% obtained by AFLP marker. The average site produced by each SSR primer was 8.6, but the average site produced by each AFLP primer combination was 68.67. Compared with SSR marker, AFLP marker could be used effectively to evaluate population's genetic diversity. According to the results of cluster analysis with UPGMA by the two methods, the cluster graph by AFLP marker could be better to response the true genetic relationship amang 17 populations. |
