[en] The pollen, ovary and whole plants of wheat in spike forming stage, ear sprouting stage and the end of flowering stage were irradiated by ⁶⁰Co γ-rays. The seed setting rate in the treated generation were calculated. The survival rate of M₁ plants, the mutation rate and the mutant types in M₂ were investigated. The results show that the optimal dose for irradiation of wheat living plants is 0.206 to 0.516 C/kg(800∼2000 R) that is only one tenth for irradiation of dry wheat seeds, and the whole mutation rate, beneficial mutation frequency and percentage of beneficial mutation for irradiation of living plants are 50 ∼57%,, 22∼24% and 83∼127% higher than that for irradiation of dry seeds, respectively. The results also show that in the same exposure range the smaller exposure rate has more effects. The optimal exposure rate is 7.74∼12.9 mC/kg (30∼50 R) per minute