Plant-Breedixg for Farmers. 167 



being careful to get all of the product and avoid cutting or injuring the 

 tubers as much as 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 the field to avoid getting the 

 hills of the 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 die 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 now is to select out from 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. Remember that 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 can be thrown to- 

 gedier 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 as a matter 

 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 that 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. Weight the 

 product of the remaining tuber-units, examine the tubers more care- 

 fully as to their character and uniformity of size in the tuber-unit and 



