476 MUTATION AND PLANT BREEDING 



Bulked F 2 generation progenies by F] generation families of 

 the four crosses A (YT32 x YT13), B (A18 x YT32), C (C12 x YT32), 

 and D (CI 2 x B35) were tested in a replicated yield trial in F 4 genera- 

 tion (1957). From each treatment in each of the crosses the highest and 

 the lowest yielding F 2 generation families were chosen from the Fi 

 generation family showing the maximum range in yield of dry 

 fruits. Table 6 shows the comparative values of the treatment means 



Table 6. — Yields in Pounds of the F 2 Progenies from the Fj Family Showing 

 Maximum Range in Yield in F 4 , 1957.* 



Cross 



B 



D. 



*a = high, b = low Fs progenies selected for variance tests in Table 7 and Figure 3. 



and the differences between the high and low selections by treat- 

 ment. Each selection was grown in a nursery row in 1958. Twenty 

 plants were harvested individually from each row and tested as F 5 

 plant progenies in the F 6 generation in blocks of P, PX, F, and FX. 

 The selections from crosses B and C were tested in 1959, those from 



