Evaluation of genetic diversity and relationshipsin orchardgrass (Dactylis glomerata L.) germplasm based on SRAP markers

Abstract

The present study is the first report of characterizing the levels and patterns ofgenetic diversity in 60 orchardgrass accessions from four continents by sequence-related amplified polymorphism (SRAP) markers. Twenty-one primer pairs were used to produce 480 bands, of which 405 (84.38%) were polymorphic. The genetic similarity coeffic ients (GS) varied from 0.5863 to 0.9686 among the 60 collections, with an average of 0.7891. The genetic diversity of orchardgrass from China and the United States of America were found to be higher than that found in other countries. The dendrogram and principal component analysis realized from these markers clustered the materials into four main groups. The cluster analysis showed that orchardgrass from Australia was different from other collections in genetic diversity. Accessions from the same continent were classified into the same group, indicating that the genetic diversity of orchardgrass and the entire genetic basis of cultivars used in a continent is narrow. Furthermore, cluster analyses suggested that there is correlation between karyotype and morphological characterizations according to the analysis of the five subclusters that clustered from the first group. The information given by SRAP markers was concordant with the morphological variability and karyotype. This showed SRAP marker system could be used efficiently in the study of genetic variability and the evolutionary history of orchardgrasses. Based on the analysis of genetic diversity and relationships, the appropriate strategies for collection and conservation of germplasm resources can be developed and this in turn would help breeding of orchardgrass. Key words: Genetic diversity, genetic relationship, germplasm, orchardgrass, sequence-related amplified polymorphism