Potato Failures. 
17 
tively small lots and kept at as even a temperature as possible. 
Spreading the tubers on the cellar floor where they are exposed to 
the light and air five or six weeks before planting is a good prac¬ 
tice. This treatment usually produces strong, hard sprouts after 
planting, which develop rapidly and are better able to resist the 
attacks of fungi. 
Developing a Disease Resistant Variety .—Different varieties 
vary greatly in their suceptibility to 'disease when grown under 
the same conditions. Even plants of the same variety often show 
considerable difference in their power to overcome disease. It is 
possible that by crossing plants which show marked disease-resist¬ 
ing power, a desirable variety might be originated, and later be 
gradually improved by constantly selecting seed tubers from the 
plants which show the greatest disease-resisting power. 
Seed Selection. —Prof. *Bolley’s work on potatoes indicates 
that small tubers from a vine which produced mostly large tubers 
of desirable form and size, have greater seed value than large, poorly 
shaped tubers from a strain of potatoes which habitually produced 
small tubers. His experiments also indicate that when pieces of 
equal weight from small and large tubers of the same vine were 
planted, there was not sufficient difference in the yield to be no¬ 
ticeable under farm conditions, providing all tubers were normally 
mature. Our experiments and observations agree quite closely 
with those made by Prof. Bolley, but it has been observed that 
elongated and ill shaped tubers are usually developed on diseased 
vines. 
Carefully selecting smooth, round tubers and rejecting all 
those showing any signs of infection, gave excellent results. In 
selecting tubers for seed, the disease-resisting power of the plant 
should also receive careful consideration. Diseased plants are not 
only apt to produce abnormally developed tubers, but the tubers 
ars also usually infected. Such seed often produces weak plants, 
which frequently suffer severely from the attacks of fungi. Success 
or failure depends much on the quality oj seed tubers used. 
No commercial grower can afford to use seed without know¬ 
ing something of its past history. Those who “import seed” will 
find it cheaper in the end to pay more for seed and buy only from 
men who are known to give careful attention to the quality of 
their seed. 
Some of our most successful growers have obtained good 
results from carefully selecting home grown seed just before or at 
digging time. This practice requires some ability and involves a 
little extra expense. As stated before, the size of the seed tuber 
* N. D. Agr. Exp., Bulletin 30. 
