Abstract

Evergreen azalea cultivars as the important ornamental shrubs and pot plants have been developed based on the genetic resources of Japanese wild azaleas. Rhododendron ripense Makino is one of the representative wild azalea species endemic to West Japan and the ancestral parent of evergreen azalea cultivars. In this study, we focused on this large flowered riverside azalea and the genetic contribution to azalea cultivars was evaluated by means of SSR markers. The results of PCoA using SSR data made plot distributions, which would reflect the taxon and genetic relationship between cultivar groups and their ancestral species. All individuals of R. ripense which classified in subsection Scabra makes distribution group apart from R. kaempferi and R. kiusianum group which classified in subsection Tsutsusi. The cultivars of R. ripense, Ryukyu azalea (R. × mucronatum) and ‘Oomurasaki’ (R. × pulchrum) are all included in this R. ripense plot group. These results of this study suggested the important genetic contribution of R. ripense to the development of these azalea cultivars.

Keywords: Ancestral parent; Breeding history; Evergreen azalea; Genetic resources