Breeding for Heat Resistant and Perpetual Flowering Azaleas

(1)落叶杜鹃花和杜鹃花耐热性的引进：在鹿儿岛地区高温高湿条件下生长的杜鹃花与杜鹃花eriocarpum×Kurume杂交的F_1杂种成活苗表现出耐热、耐湿的特点。(2)平户杜鹃花的永久开花引种：oldhamii×Hirado杜鹃花杂交的F_1杂种大部分在初秋至冬末开花。在平户杜鹃花中发现了永久开花的特性。(3)常绿叶片导入落叶杜鹃花：以红木为种子/花粉亲本的杂种F_1均有常绿叶片。将红木的常绿特性引入到F_1杂交苗木中。(4)重瓣花导入eriocarpum×Kurume杜鹃花杂交种：以杜鹃花为花粉亲本杂交的F_1杂种中，近50%的杂种具有双瓣花。说明杜鹃花的管中管性状控制基因具有遗传显性，基因型为杂合型。(5)落叶杜鹃花、杜鹃花和平朵杜鹃花花色的改良：落叶杜鹃花与eriocarpum×Kurume杜鹃花杂交的F_1杂种，花色以浅紫红色为主。oldhamii×Hirado杜鹃花杂种F_1的显性花色为浅紫红色，隐性花色为橙红色，亲本间的中间色。说明控制飞燕草素产生的基因不具有遗传显性，平户杜鹃在飞燕草素色素沉着上具有杂合基因型。

(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.