Canada Dept. Agr. Dom. Exp. Farms, Bul, 90. Popular edition 1918
The Potato in Canada: Its Cultivation and Varieties. p. 6.
W. T. Macoun
Dominion Horticulturist

Improvement by Hill Selection

After a variety has been originated, and after its general characteristics have been sufficiently fixed to introduce it, a variety may be changed, to some extent, by careful selection. This may be undertaken for the purpose of increasing the yield or to obtain a variety which is earlier or later, shallower in the eye, or of better shape. Selection may also be made to obtain a potato which is more resistant to disease and drought, better in quality, or with a higher percentage of starch, but while selection is desirable there needs to be more experimental evidence to show that marked, permanent changes in a variety can be made in this way.

The most accurate way to carry on hill selection is by the individual tuber or tuber-unit method by which the yield from each individual tuber is kept separate.

A simple method of selection, and one which will be found to give good results, is to dig enough of the general crop by hand each year so that enough seed can be selected from good hills to give sufficient quantity of seed for the general crop. By this method the poor hills including potatoes of low vitality and those affected with disease are eliminated and the standard raised. This is perhaps the best method of selection for the average farmer.

While the methods of selection described are mainly for the purpose of increasing the yield, it is desirable to select at the same time for purity, trueness to type, improvement of shape of tuber, resistance to disease, and anything else which will improve the value of the crop.