474 MUTATION AND PLANT BREEDING 



in a highly satisfactory manner. The frequency distributions of 

 the F 2 progenies for the three crosses are shown in Table 4. The F 4 

 frequency distributions of the highest yielding F 2 lines from the 

 three crosses are shown in Table 5. 



It is apparent from Table 3 and Figure 1 that radiation reduced 

 the means and increased the variances. It appears also that the 



Table 4. — Frequency Distribution of the F 2 Progeny Means in the F3 



Generation, 1956. 



Class mark, lbs. 



Cross Treat- 



ment 0.83 1.10 1.38 1.65 1.93 2.20 2.48 2.76 3.03 3.31 



P 



PX 1 15 



F 



FX 2 



II P 



PX 

 F 

 FX 



III P 



PX 

 F 

 FX 



Table 5. — Frequency Distribution of the F 4 Means of F 2 Progenies Selected on 



F 3 Performance, 1957.* 



Class mark, lbs. f 

 Cross Treatment — 



14.08 15.69 17.30 18.91 



I F 1 5 2 



FX 1 4 5 1 



II F 1 1 4 



FX 2 1 



III F 2 3 



FX 3 2 



*The variation in number of progenies per cross resulted from influence of market grade. 

 tClass interval equals LSD = 1.61 lbs. 



