To explore an efficient way of breeding for Louisiana irises, the effects of 60Co-γ rays irradiation at 0、100、200、300 Gy, respectively, on self-crossed seeds derived from 6 cultivars were investigated. The results indicated that, compared to CK, the improvement for seed germination and survival rate, as well as increase for F1M1flower stalk height and flower diameter could be achieved by 100 Gy of irradiation. The seed survival rate decreased dramatically through 200 Gy of irradiation, which showed a significant lethal effect. ≤ 200 Gy irradiation could promote the flower color segregation of F1M1 plants in 5 cultivars. The more the dose was, the higher the segregation rate was. Highly significant lethal effect was observed in the irradiation of 300 Gy 60Co-γ rays, which could decrease the seed survival rates to lower than 2% in 6 selected cultivars. As a resuslt, 100 Gy could be selected for improving seed germination and seedling production while 200 Gy could be selected for mutant breeding. 300 Gy is not suitable as the dose of irradiation breeding. The result provides a reference for the application of irradiation breeding technology on Louisiana irises.