90 h 



80 



70 



S 60h 

 iij 



05 



50 - 



O 40 - 



d 



2 30 h 



20 



10 f- 

 



1 — r 



CONTROL 



750r 



9.5 



FIGURE 5. Comparison of two curves based on 



the weight of normal and irradiated rye seeds. 



Note: dark solid line is control; broken line 



is for seeds exposed to 750 r. 



ordinary field conditions. These [control?] 

 ears sometimes exceeded normal size by one 

 and a half times (Fig. 4). But especially strik- 

 ing was the size of the grains which approached 

 that of Polish wheat. In order to compare the 

 weight of the initial [control] material with the 

 weight of seeds obtained from irradiated plants, 

 we determined their weight on torsion scales, 

 handling each seed separately. On the basis of 

 these facts, two variable curves were construc- 

 ted. By examining the left curve we can see that 

 in the initial [control] material weeds weighing 

 15. 5 milligrams were most common and that 

 they varied from 9. 5 to 33. 5 milligrams, while 



in the right curve (weight of seeds obtained 

 from irradiated material) a weight of 3. 95 mil- 

 ligrams was predominant, a weight which does 

 not even occur in the initial [control] material 

 (Fig. 5). The weight of the experimental seeds 

 varies from 21. 5 to 51. 5 milligrams. A com- 

 parison of these two curves points up the large 

 size and uniformity of the irradiated grain, 

 which from the economic point of view gives it 

 a great advantage over the initial material. 



An analysis of similar factors concerned 

 with the yield of non- irradiated and of the irra- 

 diated shoots shows that all curves based on 

 individual characteristics tend to shift to the 

 right [for the irradiated material]. 



From Table 6 we can see that the average 

 number of ears on a control plant is 4. 5, while 

 plants exposed to 250 r have on the average 

 nearly 12 ears. Then as the X-ray dosage is 

 increased, the number of ears tends to diminish; 

 however, it does not approach the control until 

 a dose of 2000 r is reached. 



Only doses of 4000 and 8000 r which have to 

 be considered strong doses, cut the average 

 number of ears per plant to three, i. e. , they 

 give a number which is smaller than the con- 

 trol (Fig. 6). 



If we analyze the column with the number of 

 seeds, we shall see a similar picture: the num- 

 ber of seeds triples with a dose of 250 r, then 

 it begins to go down gradually, and as for the 

 number of ears, the number falls below that of 

 the controls with doses of 4000 and 8000 r 

 (Fig. 7). 



The diminution of the number of underdevel- 

 oped and diseased seeds in plants irradiated by 

 beneficial doses of rays, as compared with the 

 controls, should also be noted. In the controls 

 48 out of 135 seeds, 35.5%, were underdeveloped 



Table 6 

 (based on the data of Breslavets, Afanas'eva, and Medvedeva, 1932*) 



19 



