nvbom: vegetativelv propagated species 



267 





Figure 3. — Close-up of the cobalt pot. Arrow indicates upper position 

 of the source. 



The method mostly used for the irradiation of fruit trees is 

 shown in Figure 1. Young, 1 -year-old trees are taken from the nursery 

 in the spring the second year after budding and placed at the cobalt 

 source so that the source is closer to the tip than to the root. By adjust- 

 ing the inclination of the trees we may get the killing dose of 10,000 r 

 at the tips and the physiologically rather harmless dose of 2,000 r at 



