A transcriptome analysis of two apple (Malus × domestica) cultivars with different flowering abilities reveals a gene network module associated with floral transitions

•‘Yanfu No. 6’ was the bud mutation firstly studied the mechanism of floral transition.•Low gibberellin level was conducive to floral transition.•High cytokinins level was good for floral transition.•The flowering difference of those two cultivars was linked with sugar and hormone.