PROBLEM TO BE SOLVED: To provide a new technique for reducing the high temperature disorder of rice grasses.SOLUTION: In the method for reducing the high temperature disorder of the rice grasses, the expression of any of following genes (A), (B), (C) is suppressed in the rice grasses. (A) a gene encoding a protein comprising the specific amino acid sequence； (B) a gene encoding a protein comprising the amino acid sequence in which one or a few amino acids of the specific amino acid sequence is lost, substituted, or added and reducing the high temperature disorder when the expression is suppressed in the rice grasses； and (C) a gene encoding the protein comprising the amino acid sequence having homology of 70% or more of the specific amino acid sequence and reducing the high temperature disorder when the expression is suppressed in the rice grasses.
