Molecular Typing and History of the Provins Roses Horticultural Group

摘要

A molecular typing analysis by Randomly Amplified Polymorphic DNA (RAPD) was performed on the large collection of Gallica roses from the conservatory of the 'Roseraie de la Cour de Commer' (France; 281 cultivars). A Principal Components Analysis (PCA)of die PCR data produced a map of distances between varieties. The identification of varieties by date of creation and breeder reveals the occurrence of two allele flows in opposite directions during the domestication history (XIX~(th)-XX~(th) centuries) of this horticultural group. The first flow corresponds to an increased molecular polymorphism of PCR fragments resulting from a higher heterozy-gosity. This increased polymorphism is due to extensive crosses between Gallica varieties and selection ofcultivars with original morphologies and hybrid vigour. The second flow corresponds to achievement of inter-specific crosses of Gallica (4n) varieties by Rosa chinensis (2n) and parent cultivars; these crosses result in introgression of chinenses characters (red coloration of young follicles, recurrence) together with some decrease of the molecular polymorphism probably due to some reduction of poly-ploidy and/or heterozygosity. The description in the horticultural literature of the pollination practices suggests that the many Gallica varieties corresponding to the first allele flow were created by productive breeders using simple cross intraspeciflc pollinations between Gallica cultivars. The few varieties corresponding to the second flow were createdby careful breeders who practised strict interspecific pollinations between Gallicas and Chinenses roses.