Genetic diversity analysis of cocksfoot (Dactylis glomerata L.) accessions with sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeat (ISSR) markers
Sequence-related amplified polymorphism (SRAP) and inter-simple sequence repeat (ISSR), two advanced molecular markers for genetic research in grass and forage, were used to analyze the genetic diversity among 44 accessions of cocksfoot collected from seven countries and regions. 21 SRAP primer combinations generated 476 bands, of which 401 were polymorphic (84.24%). Using 12 ISSR primers, 100 polymorphic bands out of 115 bands in total were generated (86.96%). The coefficient of genetic similarity from SRAP and ISSR data ranged from 0.6838 to 0.9686 and from 0.6935 to 0.9231, respectively. Based on unweighted pair group method with arithmetic mean (UPGMA) cluster and principal component analysis (PCA) on a series of genetic characteristics, all accessions were divided into three clusters and four clusters using two markers, respectively. Those, accessions collected from the identical continent were classified into the same cluster, suggesting the geographical distribution of genetic diversity of cocksfoot. The genetic diversity of Chinese cocksfoot except for three Chinese cultivars was rather rich and greater than that of other regions. We proposed that both SRAP and ISSR markers were considered as useful tools for evaluating the genetic diversity of cocksfoot. Especially, SRAP detected more variance and gave clearer cluster groups.
Keywords: Cocksfoot, genetic diversity, sequence-related amplified polymorphism (SRAP), inter-simple sequence repeat (ISSR), germplasm