66 The Potato 



fifty to one hundred of the best tuber-units, — best, that is, in jneld, 

 uniformity of product, color, shape, etc. After the potatoes are dug 

 and the product of each tuber-unit is laid out separately, the real 

 work of selection begins. The following are the important steps in 

 this process : 



(1) Go over the field and study the tuber-units in a gross way 

 until you have well in mind the variations in yield and the gen- 

 eral uniformity of the tubers in the various tuber-units. Re- 

 member that the total yield is not the only important character. 

 What one wants is to discover those tuber-units which have the 

 largest yield of good merchantable potatoes of the best shape and 

 appearance. Size up the field as a whole with reference to these 

 characters. 



(2) Go over each row carefully and throw out all of those tuber- 

 units which can be clearly seen to be inferior ; these may be thrown 

 together and placed with the general crop of potatoes. For the 

 interest of the grower, however, it would be well to weigh the prod- 

 uct from some of the light-yielding tuber-units and preserve the 

 figures for the sake of showing the extent of variations occurring. 

 By this first discarding process the number of tuber-units will proba- 

 bly have been reduced to two or three hundred. It is very prob- 

 able that in some cases one or more of the hills of a four-hill tuber- 

 unit will not grow. In such cases the tuber-unit will have to be 

 judged in proportion to the number of hills actually grown. 



(3) Now provide yourself with scales of some handy pattern 

 like the ordinary counter scales used by grocers, with which the 

 product of each tuber-unit can be easily and quickly weighed. A 

 satisfactory scale should weigh accurately to at least a half ounce. 

 Weigh the product of the remaining tuber-units, examine the tubers 

 more carefully as to their character and uniformity of size in the 

 tuber-unit and select about fifty of the best units. These fifty 

 units should naturally be from those marked as having good healthy 

 vines in the first examination before digging, unless all of the vines 

 at that time were in fairly good condition. In making these final 

 selections, if some hills in the tuber-unit are missing, the comparative 

 yield can be easily calculated. If one hill is missing, a comparative 

 yield for four hills is obtained by increasing the weight from the three 

 hills by one-third. If two hills are missing, a comparative yield for 

 four hills would be double that obtained from the two hills. If more 

 than two hills are missing, discard the unit entirely. 



