BULLETIN OF THE 
No. 195 
Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief. 
May 20, 1915. 
(PROFESSIONAL PAPER.) 
POTATO BREEDING AND SELECTION, 
By William Stuart, 
Horticulturist, Office of Horticultural and Pomological Investigations. 
CONTENTS. 
Page. 
Introduction 1 
Potato breeding and selection defined 2 
Limitations of breeding and selection 2 
Early attempts at potato breeding 3 
Technique of potato breeding 6 
Pollen-producing varieties 9 
Results of experimental crossing 11 
Reciprocal crosses 15 
Varietal affinity 1G 
Page. 
Potato crosses made in 1910 17 
Method of growing and testing seedlings 18 
Seedling inheritance in the Fi generation 26 
Potato improvement by selection 21 
Early selection experiments 22 
Selection methods 27 
Departmental investigations 29 
Summary 35 
INTRODUCTION. 
The increasing commercial importance of the Irish potato as an 
article of human diet and its adaptation to widely varying climatic 
conditions have served to extend its cultivation throughout most of 
the agricultural sections of the United States. 
Although the potato crop now ranks sixth in agricultural impor- 
tance in the United States, it has by no means assumed the position 
that its wide use as a table food would seem to justify. Our present 
average annual production of potatoes is only about one-fifth that 
of Germany. This wide variation in production between Germany 
and the United States may be partially accounted for by the fact that 
50 per cent or more of the German crop is used either for stock food 
or for conversion into starch, alcohol, or other industrial by-products. 
The American potato crop, on the other hand, has no such outlet for its 
surplus tubers, since less than 1 per cent of the crop is used for indus- 
trial purposes. Moreover, the per capita consumption of potatoes 
in Germany is about two and one-half times as great as it is in this 
country. These two factors account in large measure for the very 
79257°— Bull. 195—15 1 
