The present invention relates to a novel use of MADS-box genes, particularly, a novel use of MADS-box gene selected from a group consisting of a gene having a nucleotide sequence set forth in SEQ. ID. No 1 containing a nucleotide sequence encoding MADS-domain, a gene having a nucleotide sequence set forth in SEQ. ID. No 2 containing a nucleotide sequence encoding MADS-domain and a gene encoding an amino acid sequence having at least 85% homology within the region other than MADS-domain, for the regulation of fruit and seed development. MADS-box genes of the present invention can be effectively used for the regulation of parthenocarp fruit formation as well as the development of fruit and seed in a plant by controlling active gibberellin synthesis via generating a transgenic plant containing the gene of the present invention.