ESJ58 シンポジウム S14-2
Nobuhiro Kotoda (National Institute of Fruit Tree Science)
The long juvenile phase characteristic of woody plants, including fruit trees, makes their breeding cycle slower. The juvenile phase of apple generally lasts from four to eight years or more and that of citrus lasts seven to ten years. In the case of fruit breeding, the most important traits for selection are related to the fruit itself. Therefore, various practical techniques to accelerate flowering and fruiting of seedlings in the juvenile phase have been considered for years. However, little is known about the physiological and genetic factors involving the transition to flowering in fruit trees.Based on studies of Arabidopsis and other plant species, much effort has been devoted to unveil the molecular mechanism of flowering and to manipulate the flowering time in horticultural trees since the last decade. In this context, we have searched for the genes that maintain the juvenile/vegetative growth or induce the transition to flowering in apple. As a result, transgenic apples expressing the antisense RNA of MdTFL1 (an apple ortholog of TFL1) or the sense RNA of MdFT1 (an apple ortholog of FT) showed precocious flowering. In this symposium, the functions of the TFL1/FT family genes that would be responsible for the plant life cycle in apple and citrus will be discussed as well.