582 Reading-Course for Farmers. 



Digging the selection-field. The digging of the field grown for selection 

 purposes requires considerable care, and here hard work is necessary. Dig 

 each four-hill unit grown from the same tuber separately, being careful to 

 get all of the product and avoid cutting or injuring the tubers if 

 possible. Carefully place the product of each four-hill tuber-unit 

 together at one side of the row, and if it is a tuber-unit marked with a 

 stake in the field examination, keep the stake with the product of the 

 unit. A good way to dig in order to avoid getting the hills of different 

 tuber-units mixed, is to dig across the field, in a direction at right angles 

 to the direction the rows were planted. First dig the four hills of the 

 first tuber planted in the first row, then the four from the first tuber in 

 the second row, then the same in the third row, fourth row, etc., through 

 the field. Next dig the four hills from the second tuber planted in the 

 first row, then the four from the second tuber in the second row, etc. 

 By this method of digging, especially if the hills are rowed both ways, 

 there will be little danger of mixing the product of the four-hill units. 

 Making the selections. The problem after digging is to select fifty 

 to one hundred of the best tuber-units, — best, that is, in yield, uniformity 

 of product, color, shape, etc. After the potatoes are dug and the pro- 

 duct of each tuber-unit is laid out separately, the real work of selection 

 begins. The following are the important steps in this process: 



(i) 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 general uniformity 

 of the tubers in the various tuber-units (Fig. 3) . Remember that the total 

 yield is not the only important character. What one wants is to dis- 

 cover those tuber-units which have the largest yield of good merchant- 

 able 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 product from some of 

 the light yielding tuber-units and preserve the figures for the sake of 

 showing the extent of variation occurring. By this first discarding 

 process the number of tuber-units will probably have been reduced to 

 two or three hundred. It is very probable 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 



