Abstract:

The dry seeds of three sorghum (Sorghum bicolor(L.) Moench) varieties, 654, ICSV111/1022 and BTx623, were irradiated by 60Co-γrays with 4 dosage levels. The morphologic and physiologic variations at germination and seedling stage were investigated and the appropriate dosage levels of 60Co-γray for different sorghum genotypes were estimated.The seed germination energy and germination rate were firstly promoted when the dosage level was lower than 300Gy，and eventually inhibited when the dosage level was increased. The seedling growth and vigor index were declined gradually with increasing dosage. The activities of protective enzymes SOD, CAT and POD were elevated gradually with increasing dosage. Significant negative correlation existed among seedling growth, vigor index and dosage, while the activity of protective enzymes had significant positive relationships with dosage. The results suggested that the interference effect could be evaluated by the parameters of germination rate, seedling growth, vigor index, SOD, CAT and POD activity in M1 plants. The irradiation endurance of 3 varieties was ICSV111/1022>654>BTx623. The suitable irradiation dosage for irradiation breeding of 3 sorghum varieties was determined within the range of 300~700Gy.