Control of cell cycle is important in crop breeding, and it is demanded to develop, through the control, technique for modifying the multiplication of plant cell, technique for modifying the development/differentiation of plant individual and plant genes for use therein. It has been clarified that plant 3Rmyb gene is a factor indispensable for the multiplication of plant cell. Thus, there are provided, with the gene as a target, technique for modifying the multiplication of plant cell and technique for modifying the development/differentiation of plant individual, and there can be obtained a plant and plant cell retaining modified cell multiplication and development/differentiation. These enable development of a plant with desirable properties, such as amelioration of hypertrophy of specified organ, male sterility or stress resistance.
