230 The Potato 



there is any disease in the crop, the practice of leaving the 

 tubers in the ground for a time after they have matured 

 has a distinct advantage. The infected tubers start to 

 rot in the ground, and when they are dug they can easily 

 be discarded. Otherwise they are stored with the sound 

 potatoes and frequently cause a great deal of rotting. 



The progressive grower of potatoes will have on his 

 farm a breeding plot on which he is attempting to isolate 

 one or two superior strains of the variety which he is 

 growing. He ought to be constantly on the watch for 

 plants which show promise, and bring in the tubers pro- 

 duced by these for a tuber-unit test. Some time during 

 the growing season the farmer should go through his 

 commercial field and stake any plants which show quali- 

 ties of unusual vigor, disease-resistance, desirable habit 

 and so on. The product of such plants should be dug 

 by hand, bagged separately and records taken as to 

 uniformity, size, weight and so on. A consideration of 

 the data taken on each plant will show the grower whether 

 or not he should keep the tubers for further growing and 

 selection. 



Methods of digging 



The method employed in getting potatoes out of the 

 soil will depend a great deal on the area planted, the 

 type of soil and the cheapness of labor. Formerly, all 

 potatoes were dug by hand with spades or forks. Later 

 on, many growers used an ordinary plow to lift them. 

 Then a special type of plow, the shovel plow, was em- 

 ployed. Later came the various types of mechanical 

 diggers. 



Small plantings of potatoes must always be dug by 

 hand, because of the high cost of the digging machines. 



