According to the present invention, a technique of increasing the frequency of genetic recombination in genomic DNA of a plant is established. Such technique comprises: introducing a restriction enzyme gene that can be expressed in a target plant cell into the plant cell and causing the restriction enzyme gene to be transiently expressed so as to induce genetic recombination of genomic DNA or introducing a promoter and a restriction enzyme gene using the Agrobacterium method so as to induce genetic recombination of genomic DNA.
