ot is still
open to discussion.

There are those who maintain that it is just as practical to develop a
dwarf, early variety of corn in the middle latitudes with careful
selection as it is to develop a variety of equal earliness when the
planting is done in the north. These maintain that the reason the
dwarf, early varieties of corn are not normally developed in the middle
latitudes is because the selection in those places is usually made from
the large plants which yield well, instead of from the small, early
plants, such as would be naturally selected at the north.

By the same reasoning it is held that the constant growing of any
species or variety in the northern latitudes does not increase hardiness
but only enables us to determine which is hardy, thereby enabling us by
selection to increase the hardiness of our varieties.

[Illustration: Cat-leaf weeping birch and shrubbery on campus of
Agricultural College at Fargo, N.D.]

We must admit that this reasoning has a sound scientific basis, its
principal weakness at the present time being that there has not been
enough experimental work done to determine how general and constant its
application is.

However true it may be as a scientific principle, we have on the other
hand the undoubted fact that varieties of certain plants, like the
cauliflower, are so strongly modified by environment that the varieties
disappear altogether as such unless the breeding plants are grown under
very definite conditions. It is well known that cauliflower seed can be
grown, for instance, only in certain parts of Europe around the North
Sea and to a limited extent in the vicinity of Seattle, and that
cauliflower seed from any other region produces plants which not only
lose all varietal characteristics but which scarcely resemble
cauliflower at all.

As an illustration of this same principle millet affords an excellent
example. Grown at the north for a number of years, without change of
seed, it becomes short with stiff straw and very large heads, yielding a
large quantity of seed. When grown as far south as Tennessee for a
period of five years only, it assumes a very different character, being
tall and leafy with small heads and not very productive of seed. It
might be possible by very rigid selection to develop a variety of millet
that would tend to be tall and leafy even in the north, but it is
doubtful if it would remain so, and the difficulty of keeping it up to
type would be