Analysis Of Karyotype And Genetic Diversity Of Elytrigia Repens

Elytrigia repens,the perennial grass of Elytrigia genus of Gramineae, had potential value utilized for turf and forage, which had plenty of rhizome, strong spreading ability, and good cold-resistance, trample resistance, shade tolerance, humidity resistance and drought resistance. The genetic diverdity of Elytrigia repens germplasms from the National Germplasm Bank of USA was studied by using chromosome karyotypes and ISSR maker.1. The ploidy, numbers and morphological characteristics of chromosome of 15 Elytrigia repens germplasms were studied and 4 germplasms of E. intermedia, 3 germplasms of E. elongata, 1 germplasm of E. alatavica were used as referrence. The results indicated that 1) all 15 germplasm were hexaploid with abundant chromosome morphotype and could be grouped into 5 types (M, m, sm, st and sat). Out of 15 germplasms, 7 carry satellite, approximately accounted for 50%. Evolution trend of chromosome karyotype showed that the evolution of more advanced were ER020, ER117, ER014 and ER039. Karyotype type of ER020 belongs to 2C, is the most senior of evolution. Evolution relatively low-level were ER002, ER043, ER044. Karyotype type of ER002 belongs to 2A, is the lowest level of evolution. 2) 4 germplasms of E. intermedia were hexaploid, 3 germplasms of E. elongata were decaploid, 1 germplasm of E. alatavica was hexaploid, and all of them did not carry satellite. The type of E. repens germplasm was abundant. There were 3 types (2A, 2B and 2C). The type of E. intermedia and E. elongata were all belong to 2B. The type of E. alatavica belonged to 1B. It indicated that E. repens germplasm has good adaptability to the environment and the evolution degree of E. intermedia was higher.2. Genetic differences and kindredship among 30 samples of E. repens were studied by adopting ISSR markers method, proportion of polymorphic loci was 76%. The range of similarity coefficient was 0.60 t0 0.87. The 30 E. repens germplasm were clustered into 5 groups at dividing line of similarity coefficient 0.684 by using UPGMA cluster analysis. Clustering analysis showed that the ER004, ER059, ER057 and ER058 from Afghanistan had the shortest genetic distance. The largest distance was appeared between ER004 from Afghanistan and ER042 from Poland. They had distant phylogenetic relationship. Principal Component Analysis (PCA) for ISSR data showed that PCA supported UPGMA clustering result. The genetic diversity of germplasms from China was higher, which distributed in theⅢandⅣGroups. This might be caused by the complex habitats in China. The germplasms from similar habitats could be clustered in same group and showed a good geographical distribution pattern.