Abstract: This study dealt with the effect of NaN₃ on the physielogical damage of M₁ and the mutation frequency of M₂, when the wheat seeds were pre-soaked in water for different length of time.NaN₃ was an effective chemical mutagen. Some scientists from a broad believed that the highest mutation frequency was obtained when the pre-soaked wheat seeds were treated with NaN₃. But in this study, the mutation frequency was the highest when the dry wheat seeds were treated with NaN₃ (10^-3M, 2 hr.). So it was very effective, and convenient to treat dry wheat seeds with NaN₃.

Key words: Wheat, Mutation, Variation