<正> Herbage seeds of legume and grass (Defu, American fine stem spread alkaline grass and so on) were penetrated with 80 MeV/u 20Ne10+ ions supplied by HIRFL, NLHIAL. Average LET in plateau of Bragg curve of the ions was 120 keV/μm. Irradiation dose was 40, 60, 80, 100, 150 Gy for leguminous herbage and 15, 20, 30, 40, 50 Gy for grass herbage. Dose rate of irradiation was 3 Gy/min. Irradiation was carried out in atmosphere. Some of irradiated seeds were sown in the fields and others were used to do experiments for cytology.