A novel means for accelerating the flowering time in Rosaceae fruit trees such as apples and pears is provided, by inoculating a viral RNA into a cotyledon of a Rosaceae fruit tree seedling immediately after rooting with a particle gun technique, wherein the viral RNA is concentrated from a proliferating host infected with a recombinant apple latent spherical virus (FT-ALSV) expressing an Arabidopsis FT gene.
