Studies On Genetic Diversity In Wild Germplasm Of Elymus Nutans G. In The Qinghai-Tibetan Plateau

Elymus nutans Griseb.is a kind of perennial forage of Poaceae with high-quality, which has an important significance in livestock production in the Qinghai-Tibetan Plateau. Wild Elymus nutans from Qinghai-Tibetan Plateau and its marginal areas as the central materials in this experiment. Thirty characters were choosed to do morphology analysis for 54 accessions, Acid polyacrylamide gel electrophoresis(A-PAGE), Sequence-related amplified polymorphism (SRAP), Random amplified polymorphic DNA (RAPD) and Simple Sequence repeat (SSR) molecular markers were used to detect the genetic diversity of more than 60 accessions, The main results showed that:1. The test observationed 30 morphological traits of Elymus nutans Griseb from Gansu, Sichuan, Tibet,Qinghai, Xinjiang which average coefficient of variation of each character was 0.1605, average diversity index was 2.2118, these revealed Elymus nutans Griseb had rich phenotypic variation. Using the morphological variation data in NTsys-pc V2.1 software to do the UPGMA cluster analysis based on euclidean distance. The accessions were divided low-type plants, medium-type plants and high large-scale plants by the cluster analysis results. On the other hand, the principal coordinates analysis (PCA) based on morphological data found the first 8 principal component eigenvalue was high, their distribution can explain 76.67% of total variation, some indicators of morphological traits such as height, stem length, central of the spikelet length, bottom of the spikelet length, outer of the peristachyum length, lemma length, lemma width, palea width had higher characteristics of vector-valued, they can basically revealed the trend of the overall variation of morphology of Elymus nutans.2. Acid polyacrylamide gel electrophoresis (A-PAGE) was used to detect the gliadin genetic polymorphism of 64 accessions from Gansu, Sichuan, Tibet, Qinghai and Xinjiang.The results showed that a total of 42 bands were detected in 64 wild accessions,90.48% were polymorphic bands. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.320 to 1.000, and the average Nei's coefficient was 0.631. These results suggested that there was rich genetic polymorphism among the tested wild resources of Elymus nutans. All the accessions can be clustered into six groups at GS= 0.69 level on dendrogram. The principal coordinates analysis (PCA) reflected almost the same relationships among the studied materials as shown in cluster analysis. Moreover, the accessions from the same origin frequently clustered into one group. The findings implied that a correlation among gliadin patterns, geographical and ecological environment.3. In the study of SRAP molecular markers, twenty primer pairs produced 495 bands, averaged 24.75 bands per primer pair, which included 425 polymorphic bands with 21.25 bands per primer pair, the percentage of polymorphic bands in average was 85.39%. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.374 to 0.997, and the average Nei's coefficient was 0.745. These results suggested that there was rich genetic diversity among the resources of E. nutans tested. Through the cluster analysis and the principal coordinates analysis (PCA) found that 68 accessions can be clustered into four groups at GS= 0.77 level on dendrogram, the accessions from the same origin frequently clustered into one group, the findings implied that it shows better geographical distribution rule.4. Twenty RAPD primer pairs produced 443 bands, averaged 22.15 bands per primer pair, which included 407 polymorphic bands with 20.35 bands per primer pair, the percentage of polymorphic bands in average was 91.86%. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.265 to 0.987, and the average Nei's coefficient was 0.733. These results suggested that there was rich genetic diversity among the resources of E. nutans tested. Through the cluster analysis and the principal coordinates analysis (PCA) found that 68 accessions can be clustered into five groups at GS= 0.75 level on dendrogram, the accessions from the same origin frequently clustered into one group, the findings implied that a correlation among the wild resources, geographical and ecological environment.5. SSR molecular markers were used to detect the genetic diversity of 67 accessions of Elymus nutans Griseb. The following results were obtained:(1) Eleven wheat SSR primer pairs produced 225 bands, which included 224 polymorphic bands, the percentage of polymorphic bands in average was 99.1%. The Nei's genetic similarity coefficient of the tested accessions ranged from 0.192 to 0.872, and the average Nei's coefficient was 0.596. (2)67 accessions can be clustered into five groups at GS= 0.45 level on dendrogram. The principal coordinates analysis (PCA) reflected almost the same relationships among the studied materials as shown in cluster analysis. The findings implied that a correlation among the wild resources, geographical and ecological environment. (3)The test analysed the feasibility of using wheat SSR primer pairs in Elymus nutans Griseb.6. Mantel test revealed that the relation of genetic similarity matrix between gliadin and SRAP(r=0.4787, p=0.001),gliadin and RAPD (r=0.4373, p=0.001),gliadin and SSR (r=0.2691, P=0.001),SRAP and RAPD (r=0.8179, p=0.001),SSR and RAPD (r=0.4306, P=0.001),SRAP and SSR (r=0.4789, P=0.001) were all significant correlation.Overall, rich diversity can be observed in morphology, gliadin and DNA molecule. The genetic variance was correlated with morphology and wide geographic distribution. Some accessions with better ecological adaptability, production performance and higher application potential will be selected through the combination with the results of agronomy of Elymus nutans germplasm, which can meet the need of forage production.