After dormant seeds of 20 barley varieties were irradiated with

137

Cs

γ

-rays

the correlation of cell-nucleus volume and radiosensitivity were studied. The results showed that the dose-effect of cell-nucleus volume could be fitted by a linear regression equation y=A+Bx

and the dose-effect of seedling growth inhibition be fitted by equation

F

(

D

) =1- (1-

e

-

α

1

D

)

N

. No clear difference was found in dose-effect of nucleus volume among different types of barley. The value of nucleus volume was significantly correlated with that for nucleus volume D

50

among varieties (

r

=-0.8828

**

) . There was no obvious correlation among the D

50

values for nucleus volume and for seedling growth inhibition.