Japanese flowering-cherries called “Sakura” show various floral morphogenesis in such as the number of flowers in a cluster, flower size, shapes of petals, the number of petals, flower color, and so on. In this study, we are focusing on the variation of inflorescence structure which is possibly one of the important traits affecting ornamental quality for flowering-cherries. We investigated the lengths of inflorescence axis and peduncles in a number of selected cultivars of flowering cherries at the time of anthesis. The inflorescence types diverged widely from corymb to umbel. The expressions of genes expected to be involved in the inflorescence development were analyzed by RT-PCR. The expression of TFL1/CEN/FT homologous genes (PruTFL1, PruCEN, and PruFT), which are related to the flowering and inflorescence structure, were investigated in inflorescence axis and peduncles. Expression of PruTFL1 was hardly detected in selected cultivars. PruCEN expression was observed only in several cultivars. PruFT was highly expressed in the inflorescence axis and peduncles and the expression level was relatively higher in inflorescence. However, these expression levels were different in cultivars, and the relationship to morphological variation couldn’t be found. The expression of genes related to the biosynthesis of gibberellic acids, which are often involved in organ elongation, were also analyzed, but the expression pattern was ambiguous like the result of TFL1/CEN/FT homologous genes. We are planning transcriptome approach to found the other genes involved in the development of various inflorescences in flowering-cherries, and testing the effects of phytohormones to the inflorescence development.
