In plant, senescence is associated with various aspects of the final stage of leaf development, nutrient relocation from leaves to reproducing seeds and stress resistance, and yield which is the most important trait in crops. Thus, the increase of knowledge on the regulatory processes of plant senescence will allow us to manipulate senescence for agronomic benefit in the future. of genetic studies have been conducted with mutants, where most of studies were focused on the delayed senescence mutants which are associated with positive factors on senescence by treating EMS to Koshikari, we induced a mutant showing early senescence phenotype, which possibly enable us to identify a negative factor of senescence. The appearance of the mutant is identical before booting stage and then the mutant showed senescence phenotype rignt before booting stage whereas Koshikari have health green leaves. The clumn length of the mutant is 98cm and the panicle length is 23cm as same as those of Koshikari. The chlorophyl contents of the mutant leaves, measured by SPAD, decreased during senescence. The soluble protein contents in the mutant leaves also decreased but no differences in the constitution reolved 1D-SDS-PAGE was detected. However, an additional shotgun proteomic approach to detect the differences of the protein constitutions during the senescence in the mutant leaves will be conducted.