PLANT-BREEDING 319 



these plants, therefore, selection may be able to develop 

 a race remarkably free from this particular disease. This 

 method of combating disease may sometimes prove more 

 effective than any attempt to save the plants that are sub- 

 ject to it. 



The story of the development of the best-known varie- 

 ties of cultivated plants is a very interesting one, telling 

 how promising varieties have been discovered, and with 

 what wonderful patience they have been developed into 

 usefulness. The recent great increase in knowledge of the 

 principles of plant-breeding has made the development of 

 desirable varieties more definite and rapid than it has ever 

 been before. 



