562 THE MONTHLY BULLETIN. 



UNIFORMITY OF SIZE AND SURFACE. 



Good seed potatoes should be uniform in size, that size running from 

 about two to ten ounces in weight, and should be free from knobs or 

 second growth of any kind. Large potatoes do not cut to advantage 

 and, when cut, present so much cut surface as to render them easily 

 atfected by unfavorable conditions of soil or moisture when planted. 

 Potatoes having knobs or second growth often produce a poor stand 

 and the plants are likely to be weak, too many of them to a hill, and the 

 hills unproductive. 



We have thus far tried to show some of the external features of seed 

 potatoes which make them desirable or undesirable for seed purposes : 

 Freedom from disease; true to name and free from mixture; of a 

 medium, uniform size, and with a uniform surface. But if, after an 

 examination of a quantity of potatoes, we find that they represent all 

 of the good features we have mentioned, are we justified in asserting 

 or believing that they are good seed potatoes and will be uniformly pro- 

 ductive when planted? I have little doubt that any potato grower, 

 looking for seed potatoes, and finding them to pass such an inspection, 

 would gladly secure them without dickering about the price, as such 

 seed stock is almost as scarce as the proverbial "hen's teeth." But, 

 nevertheless, our ideal is the most productive seed and from our exam- 

 ination we can not as yet be satisfied that we have found it. We can say 

 that the potatoes possess some of the characteristics of good seed stock, 

 but we do not know that they possess all. If one will take from a sack 

 or bin of potatoes say forty tubers which will meet the above require- 

 ments for good seed; then cut these potatoes one at a time and plant 

 the pieces from each tuber side by side, he will doubtless be much 

 interested, as well as surprised, at the behavior of the plants they pro- 

 duce. It is possible that all of the plants from these forty potatoes 

 will be uniform in size and appearance ; but it is very probable that the 

 plants from some tubers will be markedly different from the plants 

 from other tubers — ^some tubers producing uniformly large and pro- 

 ductive plants, and other tubers producing as uniformly weak and 

 unproductive plants. It will be noted, therefore, that, althougli all 

 the tubers selected for the planting seemed to be equally good for seed 

 purposes, yet when actually tested some of them proved to be good and 

 others poor. Striking differences in the plants from various tubers are 

 often brought out by such an experiment, some tubers producing all 

 strong and healthy plants, and other tubers all weak and unproductive 

 plants. If the few potatoes which the unproductive plants produce are 

 saved and planted the following year they will probably either not grow 

 at all or be still less productive than the first season ; while tubers from 

 the productive plants the first year will produce uniformly productive 

 plants the second year. By continuing to select year after year in this 

 way the best tuber units, and a productive strain of seed can be 

 obtained which will meet the requirements of good seed potatoes — at 

 least good for the locality in which they were grown. The source from 

 which seed potatoes come, that is, the climatic and soil conditions under 

 which they were grown, is often quite important. Epecially does this 

 apply to potatoes grown for the early market. Seed stock groA\Ti in a 



