Inconstancy of Improved Races 773 



two heads. One of these comprises the rela- 

 tion of the average of the progeny to the excep- 

 tional qualities of the chosen parent, and the 

 other the relation of exceptional offspring to 

 the exceptional parents. 



Let us consider the averages first. Are they 

 to be expected to be equal to the unique quality 

 of the parent, or perhaps to be the same as the 

 average of the whole unselected race? Neither 

 of these cases occur. Experience is clear and 

 definite on this important point. Vilmorin, 

 when making the first selections to improve the 

 amount of sugar in beets, was struck with the 

 fact that the average of the progeny lies be- 

 tween that of the original strain and the qual- 

 ity of the chosen parent. He expressed his ob- 

 servation by stating that the progeny are 

 grouped around and diverge in all directions 

 from some point, placed on the line which unites 

 their parent with the type from which it sprang. 

 All breeders agree on this point, and in scien- 

 tific experiments it has often been confirmed. 

 We shall take up some illustrative examples 

 presently, but in order to make them clear, it is 

 necessary to give a closer consideration to the 

 results of Vilmorin. 



From his experience it follows that the aver- 

 age of the progeny is higher than that of the 

 race at large but lower than the chosen parent. 



