128 AGRICULTURE 



product if any one of the four plants has failed to pro- 

 duce uniform, desirable tubers. The potatoes produced by 

 each set of four selected for seed are put into separate sacks 

 and kept for further examination. 



Second season of tuber-unit planting. Finally, the 

 contents of each sack are inspected for the weight of mar- 

 ketable and unmarketable tubers, and other desirable qual- 

 ities of the type. From each of the four-plant units the 

 best ten tubers are to be selected for the next year's plant- 

 ing. This selected seed is planted the following year in 

 the same way as the first season, thus giving forty plants 

 to the unit instead of four. The product from the best 

 forty-hill rows is kept for, seed for the general crop for 

 the following year. By thus keeping a breeding plat for 

 seed, potatoes can be greatly improved, and the yield much 

 increased. 



The tuber-unit method can be rendered even more ef- 

 fective by making the first selection from the field instead 

 of the potato bin. This is done by going into the field 

 before the vines begin to die and marking a number of 

 i the most vigorous and desirable plants. These are har- 

 ; vested separately before wholly mature, and seed taken 

 from the best hills. 



The practise of planting for seed the small and unmar- 

 ketable potato culls can not be too strongly condemned. It 

 lessens the yield, lowers the quality of the crop and causes 

 the variety to deteriorate or "run out." 



Cutting seed potatoes. Whether it pays better to 

 cut potatoes for seed or plant the whole tuber has been 

 much discussed. It is believed by many potato growers 

 that under average conditions the yield will be greater when 

 quarters are planted than when pieces with single eyes are 

 used, and that halves will produce more than quarters. It 



