CHAPTER IV 

 POTATO BREEDING 



The cultivated potato of to-day has undergone a re- 

 markable change since its first introduction into Europe 

 by the Spaniards. Some of this change has been brought 

 about by better cultivation, but most of it is due to breed- 

 ing. The tubers of the wild »S. tuberosum were small 

 and attracted little attention. Heriot, in his report on 

 Virginia, describes the plant "with roots as large as a 

 walnut and others much larger ; they grow in damp soil, 

 many hanging together as if tied on ropes." The potato 

 as we know it has been developed by means of conscious 

 and unconscious selection and by hybridization with 

 other species. The modern potato has not only been 

 much changed by breeding, but it is now grown in widely 

 different surroundings which produce various changes 

 in the tubers. 



There are three foundations on which the increased 

 productivity of crops rests — the enrichment of the land ; 

 its tillage and care ; and the production of better varie- 

 ties and strains. The first two are concerned with the 

 environment of the crop, such as cultivation, fertilization, 

 freedom from insects, disease and so forth, and the last 

 with its heredity. We have long given attention to 

 environment; now we are studying heredity with new 

 enthusiasm and purpose. One of the "signs of the 

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