The domestication process of the Modern Rose: genetic structure and allelic composition of the rose complex

Abstract

Genetic variability among 100 old cultivated rose varieties from 13 horticultural groups was estimated by arbitrary primed (AP) PCR. Using five long (20-mer) PCR primers, 58 polymorphic DNA fragments were produced, of which 55 were highly discriminant, allowing differentiation of the quasi-totality of the 100 cultivars. A dendrogram was constructed displaying the relative genetic similarities between cultivars estimated from the presence/absence of PCR fragments. It shows the relationships between the Chinese and European founder roses, hybrid groups of the first (Bourbons, Noisettes, Portlands) and second (Hybrid Perpetuals and Teas) generations, and the most modern Hybrid Teas, produced during the history of domestication. Principal components analysis (PCA) of the same data demonstrates the occurrence of a continuous gradient of the European/Chinese allele ratio, and a considerable reduction of genetic variability superimposed with the progress of domestication. The two complementary analyses are in good agreement with the horticultural literature. They also give access to DNA fragments potentially linked to genes involved in the control of the main morphogenetic characters of various groups.