228 SCIENCE REMAKING THE WORLD 



varieties. Good normal tubers, as a rule, will sprout 

 first from the eyes on the terminal or seed end of the 

 tuber. These sprouts, if not destroyed, or too much 

 impeded in growth, will inhibit the growth of sprouts 

 from the basal eyes. If the first sprouts lack the nor- 

 mal vigour of the variety they will not prevent the 

 growth of sprouts from the more basal eyes, but sprouts 

 will be scattered over the entire tuber. This lack of 

 apical dominance in the first crop of sprouts is a sign of 

 low tuber vitality, or in other words, its inability to pro- 

 duce vigorous plants with the proper number of stalks. 

 Extreme cases of low vitality are manifested in the 

 spindliness of the sprouts, but in many cases the sprouts 

 are much below normal in growth vigour without show- 

 ing the characteristic spindliness. It is in the latter 

 case that lack of apical dominance is of service as a 

 guide. 



A great deal of the older potato research was con- 

 cerned with methods of cutting the seed tubers and 

 with the most profitable amount of seed to plant per 

 acre. In regard to certain phases of this problem the 

 results have been so uniform and conclusive that it is 

 now largely a matter of education to get them more 

 generally adopted in practice. It is generally conceded 

 that no conditions will justify planting seed pieces 

 weighing less than 1.5 to 2 ounces. With high fertility 

 and cheap seed it is sometimes profitable in some locali- 

 ties to plant seed pieces weighing even more than 2 

 ounces. More recent research has shown that the 

 low yields from small seed pieces is traceable to weak 

 sprouts produced by the small pieces. After a mini- 



