Abstract: 【Objective】The objective of the present study was to analyze the mutagenic effects and frequency of mixed particle field with high energy(CR) irradiation in winter wheat, and to compare with those of 60Co-γray irradiation. 【Method】Air-dried seeds of winter wheat cultivars ZY9 and ZH7 were used to irradiate by CR andγ-ray with the dosage of 0, 145Gy, 195Gy, 284Gy and 560Gy respectively. Irradiated seeds were germinated in the laboratory; mutants from M2 generation were screened and analyzed. 【Result】 There was obviously linear dose-effect relationship at inhibiting plant growth of these two genotypes, the damage effect of CR was higher than that of gamma rays, and the variety ZH7 was more sensitive than ZY9. The optimal irradiation dose of cosmic rays for wheat was 200 to 300Gy. Mutation phenotypes of CR treatment in M2 populations included plant height, spike type, heading date etc, the useful mutation frequency at the optimum or little higher dosage was high than that of gamma rays irradiation. The total mutation frequency and useful mutation frequency of CR treatment for ZY9 was 5.42~11.68% and 2.75~7.29%, for ZH7 was 10.35~22.12% and 6.62~10.49%, respectively, higher than that of gamma rays. 【Conclusion】These revealed the higher relative biological effect of CR treatment could induce than that of gamma rays; the more sensitive the variety was, the higher useful mutation frequency and the higher probability of screening improved genotypes would be.

Key words: Winter wheat (Triticum aestivum L.), Mixed particle field, Gamma rays, Mutants, Mutation frequency