AN ANALYSIS OF THE EFFECT OF SELECTION, 



21 



Table 17. — Inbred Plus Lines Crossed. 



Generation. 



Pi. 



F 2 . 



n 



192 

 689 



M 



5.365= 

 5.374= 



;0.041 

 = .022 



().s_M ±0.029 

 .817=*= .015 



1941 Set Alone. 



Fi 



F 2 



[Total . 

 F 3 Plus.. 



[Minus. 



Total . 



F 4 J Plus. . 



[Minus. 



42 

 279 

 605 

 395 

 210 

 303 

 270 



33 



1,789 



5.500=*=0.0S0 



5.233=*= 

 5.783=*= 

 5.767=*= 

 5.814=*= 

 6.116=*= 

 6.144=*= 

 5.879=*= 



.034 

 .018 

 .023 

 .031 

 .020 

 .022 

 .069 



1 — 0.27S=t=0 (0 1 



- .036=*= 



+ .131=*= .038 



1 Does not include culture 2054, in which the mother was not-Dichaet. 

 10 11 



Fig. 10. — Means and standard deviations for cross of two inbred plua lini 

 Fig. 11. — Means and standard deviations for cross of 1002 inbred pltu 

 and speck (1331) minus lines. 



was nearly the same as that in F b the F 2 -F 3 and F 3 -F 4 parent-offspring 



correlations were not significantly different from 0, and the means of 

 the plus and minus selected series in F 3 and F 4 were practically identi- 

 cal. This constitutes practically a proof thai the two lines did not 

 differ with respect to modifying genes. The result, while surprising, 

 is by no means highly improbable on the multiple-factor view. The 



