230 SCIENCE REMAKING THE WORLD 



arranging these names into typical groups, a very im- 

 portant but difficult task. The public and the potato 

 industry should be protected by certain restrictions 

 governing the introduction of new potato varieties. 

 Encouraging efforts are being made in this direction. 



POTATO IMPROVEMENT. Variety testing has long 

 been a favourite type of potato investigation. The re- 

 sults of this enormous amount of work have been of 

 great local importance in discovering standard varieties 

 best suited to particular climate and soil conditions, but 

 they have been of very limited general application. 

 Recent years have shown a marked decrease in the 

 number of such investigations. Much of this effort 

 is now being replaced by attempts to improve our 

 standard varieties and to develop new varieties better 

 suited to local condition. 



The potato can be improved by application of modern 

 knowledge of breeding and selection. The former 

 method consists in the actual crossing of two varieties 

 by artificially applying the pollen of one parent to the 

 stigma of the other. This is the only means by which 

 desirable characters of two parents can be combined 

 in the offspring. It is frequently desirable to combine, 

 in the offspring, immunity to disease of one parent 

 with high yield or better cooking quality of the other 

 parent, or high yield with more desirable tuber charac- 

 ters, as size, shape, shallow eyes, etc. Most of our 

 present varieties have originated as seedlings, either 

 by chance or artificial breeding. Unfortunately potato 

 breeding is fraught with many difficulties. On account 

 of long continued reproduction by tubers or for othe$ 



