Propagation 59 



Small or medium-sized roots are usually selected for 

 seed purposes since the small roots produce many more 

 plants to a bushel of seed than do larger potatoes. It 

 would seem reasonable to believe that continued use of 

 small seed would tend toward the production of a field 

 crop of small tubers but this theory has not been sub- 

 stantiated in practice. The question has been raised 

 whether, because the smaller potatoes are usually formed 

 later in the season, the practice of using these small 

 potatoes for seed would tend to produce a late strain. 

 For all practical purposes, the tendency in this direc- 

 tion, if present at all, would be so slight as to be negli- 

 gible. As the sprouts come only from the neck of the 

 potato and as the greater number of smaller potatoes 

 contained in a bushel provides a much larger total sur- 

 face area from which the buds may grow out, it is 

 quite evident that economy would result from the use 

 of small tubers in so far as the number of plants pro- 

 duced is concerned. This fact is further augmented by 

 the difficulty of disposing profitably of the small potatoes 

 on the market for any other purpose than for seed. 

 Although some growers maintain that more vigorous 

 plants are produced from the larger tubers, more sub- 

 stantial evidence will have to be secured before dis- 

 continued use of the small tubers is warranted, espe- 

 cially if they are chosen from high yielding hills. It 

 is probable that certain varieties have a greater tendency 

 to produce stringy potatoes than do other kinds under 

 the same conditions. It is evident that in case of a 

 mechanical mixture of two such varieties, continued 

 selection of the small tubers would result in the in- 

 ferior variety becoming dominant over the more de- 

 sirable one. As has been stated, however, the tubers 



