Expression patterns of several floral genes during flower initiation in the apical buds of apple (Malus × domestica Borkh.) revealed by in situ hybridization.

The apple (Malus × domestica Borkh.) is one of the commercially important fruit crops in the worldwide. The apple has a relatively long juvenile period (up to 4 years) and a long reproductive period between the flower initiation and the mature fruit (14-16 months), which prevent the fruit breeding.