The Breeding for Development of Rhododendrons and Azaleas with Heat Resistance and New Flower Colors

一些鳞片杜鹃花（LR）具有类似于万年青杜鹃花（EA）的形态特征，具有优异的蓝色花色。然而，它们的根本缺陷是缺乏耐热性。此外，经常遇到杂交不亲和性和/或杂种不育性。利用26个物种和品种进行不完全双等位基因杂交。从杂交性、耐热性、观赏性等方面筛选出2个种7个品种为优良的育种材料。利用这些材料进行了进一步的杂交，其中一些LR和R之间的初始杂交。采用高效液相色谱法对蓝色、紫色、粉红色、玫瑰色和红色杜鹃花的色素成分进行了比较。花色苷的羟基化和甲基化、黄酮醇的总量及其甲基化、花色苷和黄酮醇之间的共色素化是形成较蓝色调的重要因素， ...更多信息 花青素苷的羟基化作用似乎最为突出。通过EA/落叶杜鹃（DA）和LR/象鼻杜鹃（ER）的亚属间杂交，培育出花色丰富、观赏性强的杂交种。ER × DA和ER × LR的杂种种子均能萌发，而LR × DA、EA × DA和LR × ER的正常大小的杂种种子不能萌发。此外，在黄LR内的杂交中发现了相当严重的种间障碍。在塑料大棚中对44,665株ER幼苗进行了耐热性筛选。认为通过选择合适的亲本材料、重复杂交和严格的后代选择，可以提高耐热性。少

Some lepidote rhododendrons (LR) which have morphological characteristics similar to Evergreen Azaleas (EA) have excellent blue flower colors. Their fundamental defect is, however, their lack of heat resistance. Moreover, cross-incompatibility and/or hybrid sterility are frequently encountered. Incomplete diallele crosses using 26 species and cultivars were conducted. Two species and 7 cultivars were selected as promising breeding materials from their cross-ability, heat resistance, and ornamental characteristics. Further crosses using these materials were conducted, in which initial crosses between some LR and R. Eriocarpum, a heat resistant EA from Tokara Archipelago, were successful.Pigment components of blue, purple, pink, rose and red rhododendrons were compared using HPLC. Hydroxylation and methylation of anthocyanin, total amount of flavonol and its methylation, and copigmentation between anthocyanin and flavonol were important factors towards development of bluer hues, although … More action of hydroxylation of anthocyanin seemed to be most prominent. In the course of this analysis, an unknown yellow pigment was also revealed to be present in some rose and red rhododendrons, The possibility for another breeding approach to intensify yellow flower color was thus suggested.Intersubgeneric crosses among EA/Deciduous Azaleas (DA) and LR/Elepidote Rhododendrons (ER) were implemented to develop hybrids with intense yellow color and other ornamental characteristics. Hybrid seeds from ER x DA and ER x LR germinated, but normal sized hybrid seeds from LR x DA, EA x DA and LR x ER did not germinate. In addition, a fairly severe interspecific barrier was found in crosses within yellow LR. The necessity for polyploid breeding is suggested.About 44,665 ER seedlings were screened for heat resistance in a plastic house. It was suggested that improvement of heat resistance is possible through selection of appropriate parental materials, repetition of crosses, and strict progeny selection. Less