ARTIFICIAL AND NATURAL SELECTION 31 



Directing now our attention to the selection of cultivated plants, 

 it is manifest that this process has to start from distinct forms. 

 Obviously the choice of the starting-point is as important as the 

 improvement itself. Or rather, the results depend in a far higher 

 degree on the adequate choice of the first representatives of the 

 new race than on the methodical and careful treatment of its off- 

 spring. Unchangeable qualities determine the value of the new 

 strain, if they were present in the chosen individual; if not, no 

 selection can produce them. 



This assertion, however, has not always been appreciated as it 

 deserves, nor is it at present universally acknowledged as a first 

 principle. The method of selecting plants was discovered by Louis de 

 Vilmorin, about the middle of the last century. Before him selec- 

 tion was applied to domestic animals, and even on a large scale. 

 Vilmorin applied it to his beets, in order to increase the amount of 

 sugar in their roots. Evidently, he must have made some choice 

 amongst the numerous sorts of beets of his time, or otherwise chance 

 must have thrown into his hands exactly one of the most appro- 

 priate forms. But on this point, no historical evidence is at hand. 



Since the time of Vilmorin, selection of agricultural plants has 

 enormously gained in importance. Only of late, however, Rimpau and 

 von Ruemker in Germany, and Willet M. Hays in this country, have 

 begun to apply critical methods to the various parts of the process, 

 in order to get a better insight. All of them have insisted upon the 

 necessity of distinguishing between the first choice for a race and the 

 subsequent improvement by continued selection. The choice of 

 the most adequate varieties has to become the principle for the 

 foundation of all experiments in improving races. 



Hays clearly states the far-reaching importance of this practical 

 rule by asserting that half the battle is won by choosing the variety 

 which has to serve as a foundation stock, whilst the other half de- 

 pends upon the selection of mother plants within the chosen variety. 

 The choice of the variety is the first care of the breeder in each single 

 case, whilst the so-called artificial selection takes only the second 

 place. Half a century ago the famous Scotch breeder Patrick Shirreff 

 taught that it is quite useless to search for starting-plants for im- 

 proved races among varieties of minor value. Only the very best 

 cultivated types yield the material for further successful improve- 

 ment. 



In practice, as in systematic science, it is usual to call all minor 

 units within the acknowledged species by the same name of varie- 

 ties, without regard to their real systematic relations. Complying 

 with this custom, the principle of the choice of starting-points is 

 called by Hays "variety-testing." This testing and comparing of 

 varieties is one of the prominent lines of the work of the Agricul- 



