404 MUTATION AND PLANT BREEDING 



I would merely add that, since the beginning of the UT-AEC Coopera- 

 tive Program in 1956, we have also brought all seeds to constant moisture 

 at 65 per cent relative humidity. They are then sealed in plastic, irradi- 

 ated, and returned to the cooperator. There seems little doubt that 

 this procedure keeps sensitivity (in terms of toxicity), storage effects, and 

 oxygen effects at a minimum and the experiments are highly repeat- 

 able. 



