Rose germplasm identification and analysis with RAPD markers

Abstract

The genus Rosa consists of more than 100 species distributed widely throughout the northern hemisphere. It has been classified into four subgenera, Eurosa, Platyrhodon, Hesperhodos and Hulthemia. The subgenus Eurosa includes 11 sections. The other subgenera are monotypic. One hundred and thirty six accessions of thirty-seven rose species which include 8 sections of the subgenus Eurosa and one species each from the subgenera Hesperhodos and Platyrhodon, were analyzed using 270 random amplified polymorphic DNA (RAPD) markers with 10 primers. One hundred and nineteen accessions and 213 markers were used to calculate a similarity matrix which was clustered with the unweighted pair group method using arithmetic means (UPGMA). This data set, and original data set of 136 accessions and 270 markers, were also analyzed using the parsimony method for phylogenetic analysis. The RAPD markers distinguished between all the rose accessions and species grouped into their respective sections, except for Rosa cymosa. Therefore, classification of Rosa using RAPD data generally supports the traditional classifications. The Asian rose sections (Laevigatae, Banksianae, Bractealae, Pimpinellifoliae, Chinenses and Synstylae) were consistently separated from the North American sections (Cassiorhodon and Carolinae). The relationships among these Asian sections varies somewhat between phenetics and cladistic analysis. Two North American sections (Cassiorhodon and Carolinae) were consistently grouped together with the two subgenera, Hesperhodos and Platyrhodon. The two subgenera separated out at the same level as the sections within the subgenus Eurosa, indicating that they are more appropriately classified as sections within the subgenus Eurosa. The sections Cassiorhodon and Carolinae overlapped and are probably best grouped as one section as previously suggested. Rosa cymosa, traditionally classified into the section Banksianae, was more closely grouped with R. multij7ora of the section Synstylae in the RAPD dendrogram and one of the two cladograms.