Rose germplasm analysis with RAPD markers

The genus Rosa consists of more than 100 species classified into four subgenera, Eurosa, Platyrhodon, Hesperhodos, and Hulthemia, and distributed widely throughout the northern hemisphere. The subgenus Eurosa includes 11 sections. The other subgenera are monotypic. One hundred and nineteen accessions and 213 markers of 36 rose species that include eight sections of the subgenus Eurosa and one species each from the subgenera Hesperhodos and Platyrhodon were used to calculate a similarity matrix, which was clustered with the unweighted pair group method using arithmetic means (UPGMA). The RAPD markers distinguished between all the rose accessions, and species grouped into their respective sections. Therefore, classification of Rosa using RAPD data generally supports traditional classification. The Asian rose sections (Laevigatae, Banksianae, Bracteatae, Pimpinellifoliae, Chinenses, and Synstylae) were consistently separated from the primarily North American sections (Cassiorhodon and Carolinae). The Cassiorhodon and Carolinas sections were grouped together with the subgenera Hesperhodos and Platyrhodon. Both subgenera separated out at the same level as sections within the subgenus Eurosa, suggesting that they are more appropriately classified as sections within the subgenus Eurosa. Sections Cassiorhodon and Carolinae overlapped, and are probably best grouped as one section as previously suggested.