The following results were obtained when dry seeds of wheat Var. Zhemai No.1 and M588-1 were exposed to 20

30 and 40 krad of gamma irradiation from both

137

Cs and

60

Co sources at a dose rate of 150 rad/min with seeds treated with

60

Co gammaray as control. The morphological injuries and physiological damages in M

1

appeared to be serious with increasing dose

however the responses of the varieties were different to the sources. There was a significantly negative correlation between the single plant yield and the dose exposed

the coefficient for Var. M588-1 was -0.9886

while Zhemai No.1 was -0.9314. Results obtained through path coeficient method showed that the reduction of single plant yield was mainly caused by the decrease of effective panicle number. Dry wheat seeds irradiated with different sources resulted in plant morphological alternation and cytological changes. The rate of chromosomal aberration and micronuclei number were increased as the seeds received dose more. The coefficient between radiation dose and micronuclei rate reached 0.9726.