22 
The Colorado Experiment Station. 
to revert or change its characteristics (that is run out) if selection 
of seed is not practiced. This is particularly true of a species 
that has such a great number of varieties as the potato. Varie¬ 
ties in this way are frequently subdivided into types. In a small 
way this may be seen in any potato field. A good example may 
be found in the Improved Peachblow. Some hills will be found 
that have from one to three large tubers with possibly a few very 
small ones. The large ones are apt to be cracked so as to be un¬ 
salable. Other hills may have one large tuber with several others 
grading down to the very small specimens. Now and then will 
be found a hill with from eight to a dozen medium sized perfect 
shaped tubers. Every man has in his mind an ideal type of the 
variety that he grows. 
HOW TO SELECT SEED POTATOES 
When digging, hills will be found, all the tubers of which will 
conform to this ideal. If these tubers be saved and planted, a 
large part though not all of them ought to produce potatoes like 
the seed. These should be selected again by hills and all should 
be discarded except potatoes from those hills which approximate 
the ideal type. 
The longer this selection is carried on, the greater should be 
the proportion of tubers like the original selected type. 
The usual objection to this selection, in practice, is that at 
digging time when the work must be done, the grower is too busy 
getting in the crop to take time for improvement of future crops. 
The selecting can be done, however, without taking a great deal of 
time. When the digger is running, one man should follow with 
a basket and select the most desirable specimens of tubers from hills 
that conform to his ideal type of that variety. Ordinarily the ma¬ 
chine will leave the tubers in such shape that the individual hills 
can be separated. In this work do not look for perfect tubers 
only. Select perfect tubers from hills in which all of the tubers are 
of good shape and of sufficient number to give a good yield even 
though some of them are too small for market. 
With this system of selection enough seed potatoes ought to 
be secured in one day to plant at least one acre of land. These po¬ 
tatoes should be sacked, labeled and put in a cool place by themselves. 
The following spring they should be planted at one side of the 
field where they can be staked off from the rest of the crop. Most 
growers prefer to plant potatoes, that are intended for seed, late. 
A very rich soil is not desirable for growing seed potatoes be¬ 
cause of the tendency to produce overgrown tubers. This may 
be overcome to some extent by planting more seed to the hill or 
planting the hills closer together. When digging time comes the 
