PmFT, a Prunus mume ortholog of FT (FLOWERING LOCUS T) in Arabidopsis thaliana (L.) Heynh., was isolated and characterised to elucidate the mechanism of floral bud formation in Japanese apricot (P mume). The Japanese apricot genome contained a single locus of PmFT. PmFT consisted of a 1,473-bp open reading frame with three introns and four exons, which encoded 174 amino acid residues. The PmFT sequence showed high identity to A. thaliana FT and to FT orthologs in other plant species. Wild-type and ft-1 strains of Arabidopsis that were transformed with 35S:PmFT showed precocious flowering, indicating that PmFT has the same function as A. thaliana FT and FT orthologs in other plant species. PmFT transcripts were found in all tissues examined, with more abundant expression observed in tissues from adult trees than from seedlings.