Hayes and Garber - Cucurbit Breeding

228 BREEDING CROP PLANTS
These early studies illustrate the general mode of production
of new potato varieties. Certain methods are of value in giving
the seedlings a good start. In the latitude of Washington,
Stuart recommends sowing the seed in the greenhouse early in
March and transplanting the seedlings from 3-in. pots into the
field in May. The plants are placed in rows 3 ft. apart and
spaced at a distance of 2 ft. apart in the row. Results indicate
that seedlings producing tubers of irregular shape or those with
deep red or purple skin may well be discarded after the first
year's trial. After another year's study those strains with
undesirable characters such as low yielding ability, undesirable
shape, deep eyes, unusual susceptibility to fungous diseases and
FIG. 56. An unpromising first-year seedling. Crop of 1910. Note the
large number of small, irregular shaped tubers. (After Stuart.)
straggling or weak vine growth, should be discarded and the few
more promising types given a wide test to determine their
adaptability and value under different conditions.
Clonal Selection. The subject of bud mutations in potatoes
is a somewhat difficult one, for there are numerous reported cases
of such sudden changes. Many of the experiments were not
performed with sufficient care to furnish acceptable evidence,
although numerous apparently authentic cases of color changes
have been reported. As an illustration of carefully controlled
experiments those carried on by East (1910a) may be cited.
these studies each variety worked with was started from a single
hill. During the course of the study, five permanent changes
In