No. 565] CHANGES PRODUCED BY SELECTION 



L9 



an F 7 population with the 

 mean at 25.8 ± .09 leaves, 

 really means anything we a 

 it yields at all to selection, 

 the progress is very slow. 

 On the other hand, a con- 

 siderable gain has been 

 made in the pins selec- 

 tions. The mode rose im- 

 mediately to 29 leaves 

 when the progeny of a 29- 

 leaved plant were grown, 

 and went up to 30 leaves 

 the next generation, the 

 modal condition being the 

 same as the number of 

 leaves of the parent plant. 

 The means are 26.3 ± -10 

 leaves, 28.7 ± .10 leaves 

 and 29.2 ±.08 leaves, the 

 amount of progress being 

 — as may be seen — 2.4 

 leaves and 0.5 leaf in the 

 two successive genera- 

 tions. This result appar- 

 ently indicates a slowing 

 down of the effect of selec- 

 tion. 



The continuation of the 

 table gives the results ob- 

 tained at New Haven on 

 this same family. Here 

 there are data from three 

 generations, and these 

 data modify the conclu- 

 sions based on the results 

 obtained at Bloomfield. 

 nearly parallel the Bloomfh 



mode one class lower and the 

 Whether this slight reduction 

 re unable to say. At least, if 



7 



th plus and minus strains 

 results for two generations, 



