There is a long-lasting flower trait with a temporal color change, known as “misome-shō”, in Japanese evergreen azalea. This trait has been found in several wild Japanese evergreen azalea species, such as Rhododendron kaempferi ‘Nikkō-misome’, R. macrosepalum ‘Kochō-zoroi’, R. indicum ‘Chōjyu-hō’, and R. × hannoense ‘Amagi-beni-chōjyu’. The corollas of long-lasting flower cultivars undergo a conversion of normal corollas to sepaloid corollas due to loss of function of the MADS-box B class gene, APETALA3 (AP3) homolog. Also, the long-lasting flower trait was shown to be recessive to normal flowers and controlled by a single gene. To develop a DNA marker for selection of the long-lasting flower phenotype, we carried out a multiplex-PCR approach to detect the ap3 mutant allele related to long-lasting flower traits, and investigated the flower phenotypes in crossed progenies of 23 cross combinations and 245 individuals. The normal flower phenotype individuals in the crossed progenies were homozygous for the normal allele or heterozygous for the normal allele and the ap3 mutant allele. On the other hand, the long-lasting flower phenotype individuals in the crossed progenies were homozygous for the ap3 mutant allele of long-lasting cultivars. These results support the idea that the long-lasting flower trait is caused by a mutation in the AP3 homolog, and it has been newly clarified that any combination of these mutant alleles in long-lasting flower cultivars has the long-lasting flower phenotype. In conclusion, our data indicate that efficient selection of individuals with long-lasting flowers will be possible by using selection DNA markers linked to the long-lasting flower trait.

在日本常绿杜鹃花中，有一种随时间变化而持久的花性状，被称为“misome-shō”。这种特性已在几种野生日本常绿杜鹃花物种中发现，例如Rhododendron kaempferi 'Nikkō-misome'、R. macrosepalum 'Kochō-zoroi'、R. indicum 'Chōjyu-hō' 和R. × hannoense 'Amagi-beni -chōjyu'。由于 MADS-box B 类基因APETALA3 ( AP3) 同源。此外，持久的花性状被证明对正常花是隐性的，并由单个基因控制。为了开发用于选择持久花表型的 DNA 标记，我们进行了多重 PCR 方法来检测与持久花性状相关的ap3突变等位基因，并研究了 23 个杂交组合的杂交后代中的花表型和245人。杂交后代中的正常花表型个体对于正常等位基因是纯合的，或者对于正常等位基因和ap3突变等位基因是杂合的。另一方面，杂交后代中持久的花表型个体对于ap3是纯合的持久栽培品种的突变等位基因。这些结果支持了持久花性状是由AP3同系物的突变引起的观点，并且新近阐明了持久花栽培品种中这些突变等位基因的任何组合都具有持久花表型。总之，我们的数据表明，通过使用与持久花性状相关的选择 DNA 标记，可以有效地选择具有持久花朵的个体。