PROBLEM TO BE SOLVED: To provide a method for establishing a colza restorer line by isolating a Rf gene, especially Rf1 gene derived from a radish, identifying the structure thereof and utilizing the Rf gene. SOLUTION: Disclosed is either of the following DNAs: (1) a DNA having a specific base sequence derived from the radish; (2) a DNA having a base sequence in which one or plural bases are deleted, added and/or substituted in the base sequence described in (1), and relating to restoring sterility of a cytoplasmic male sterile individual to fertility; or (3) a DNA hybridizing in a stringent condition to the DNA having the base sequence described in (1) and relating to restoring the sterility of the cytoplasmic male sterile individual to the fertility.
