EVALUATION AND APPLICATION OF EVERGREEN AZALEA RESOURCES OF JAPAN
Among the 50 Rhododendron species native to Japan, the species in the subgenus Tsutsusi section Tsutsusi are the most important evergreen azaleas used as ornamental shrubs and pot plants. In Japan, hundreds of azalea cultivars have been selected from the diversity of endogenous species and natural hybrids since the early 17th century, the Edo era (1603 to 1867). Each cultivar group, such as Edo-kirishima, Kurume, Ryukyu, Hirado and Satsuki is developed by selection and crossing based on wild species. The wide genetic diversity within wild azalea populations together with the existing variation in cultivars and flower color and/or shape mutants are the most worthwhile genetic resources. We have been conducting a wide range of genetic research in azalea from the evaluation of genetic resources to the application for practical and molecular breeding. Genetic diversity of plants collected from wild populations and old cultivars were evaluated by means of field studies, phenotypic characterization and molecular approach. Several genes related to flower color, flower shape and flowering had been already isolated, and the relationship between characteristics and gene expression were investigated. Furthermore breeding programs using these genetic resources and genetic information are running. Progenies, with novel phenotypic traits and/or informative for genetic research, have been emerged from our laboratory.
Kobayashi, N. (2013). EVALUATION AND APPLICATION OF EVERGREEN AZALEA RESOURCES OF JAPAN. Acta Hortic. 990, 213-219
Rhododendron, breeding, genetic diversity, ornamental trait, flower color, morphological mutation, MADS-box, flowering, inter-subgeneric hybrid