Breeding for Heat Resistant and Perpetual Flowering Azaleas

(1)落叶杜鹃花和杜鹃花耐热性的导入：在鹿儿岛地区高温高湿条件下生长的落叶杜鹃花与高山杜鹃杂交F_1代的成活幼苗表现出耐热耐湿的特性。(2)平方杜鹃引入常年开花：老杜鹃×平叶杜鹃杂交的F_1代多数在初秋至冬末开花。将绿叶杜鹃的永久开花特性引入平度杜鹃花。(3)将常绿叶片导入落叶杜鹃花：以绿叶杜鹃为种子/花粉亲本的杂交F_1代全部长有常绿叶片。(4)刺梨×库鲁姆杜鹃杂交种的引种：以杜鹃为亲本的杂交F_1代有近50%的杂交种开花。(5)杜鹃花、杜鹃和平叶杜鹃花色的改良：杜鹃花与杜鹃×杜鹃杂交F_1代花色为显性浅紫红色。绿叶杜鹃×平度杜鹃杂交F_1代花色为显性浅紫红色，隐性为鲑鱼花色，亲本间为中间色。这表明控制飞雀素生产的基因不是遗传显性的，平渡杜鹃花在飞雀素的着色上具有杂合型。

(1) Introduction of heat resistance into deciduous azaleas and Kurume azaleas : Survived seedlings of F_1 hybrid from the crosses among deciduous azaleas and those from the cross of Rhododendron eriocarpum×Kurume azaleas grown under high temperature and high humid condition in Kagoshima region showed a heat and humid tolerant characteristics.(2) Introduction of perpetual flowering into Hirado azaleas : Most of the F_1 hybrids from the cross of R. oldhamii×Hirado azaleas flowered in early autumn to late winter season. Perpetual flowering property found in R. oldhamii was introduced into Hirado azaleas.(3) Introduction of evergreen leaves into deciduous azaleas : All F_1 hybrids from the crosses using R. tashiroi as a seed/pollen parent had evergreen leaves. Evergreen-property found in R. tashiroi was introduced into the seedlings of F_1 hybrid.(4) Introduction of flowers with double (hose-in-hose) petals into R. eriocarpum×Kurume azalea hybrids : Nearly 50% of F_1 hybrids from the crosses using Kurume azaleas as a pollen parent had flowers with hose-in-hose petals. It suggests that genes controlling hose-in-hose trait in Kurume azaleas are genetically dominant and genotypes of Kurume azalea are heterozygous.(5) Improvement of flower colors in deciduous azaleas, Kurume azaleas and Hirado azaleas : F_1 hybrids from the crosses among deciduous azaleas and those from the cross of Rhododendron eriocarpum×Kurume azaleas had a dominant light purplish-red flower color. F_1 hybrids from the cross of R. oldhamii×Hirado azaleas had a dominant light purplish-red flower color, recessive salmon flower color and intermediate color between parent plants. It suggests that the gene controlling delphinidin production is not genetically dominant and Hirado azalea has heterozygous genotype on the pigmentation of delphinidin.