Comparison of genetic diversity in cultivated and wild orchardgrass(Dactylis glomerata) detected by SSR markers

To reveal the genetic diversity in cultivated and wild orchardgrass,25 SSR primer pairs were used to amplify 23 accessions(including cultivar,tetraploid,diploid etc.).The average number of bands per primer pair was 10.04 and 251 clear bands were obtained of which 100 percent were polymorphic.The average genetic diversity,as measured by the polymorphism information content(PIC) was 0.33,and ranged from 0.24(A01E14) to 0.42(A01F24,A03B16).The genetic distance of 23 accessions varied from 0.106 5 to 0.606 1,with an average of 0.387 0.The mean genetic distance among 6 cultivars was 0.308 8,lower than the average of all accessions.Clustering analysis showed that 23 accessions could be divided into different groups according to the geographic distributions,ploidy,and cultivar.Principal component analysis was consistent with clustering analysis.The analysis of molecular variance indicated that the genetic variation was higher within groups than between groups.The result of comparison of genetic diversity among different groups showed that there was no significant difference between the group of wild and cultivated orchardgrass,but the genetic diversity of the tetraploid group was much richer than that of the diploid group.