espite these serious setbacks it was evident throughout the
experiment that the grafted grapes made better vines and were more
productive than those on their own roots. As an example of the
differences in yield, a summary of the data for 1911 may be given. In
this year, an average of all the varieties on own roots yielded at the
rate of 4.39 tons to the acre; on St. George, 5.36 tons; on Gloire,
5.32 tons; on Clevener, 5.62 tons. The crops on the grafted vines
were increased through the setting of more bunches and the development
of larger bunches and berries.

The grapes on the vines grafted on Gloire and Clevener ripened a few
days earlier than those on their own roots, while with St. George a
few varieties were retarded in ripening. Changing the time of maturity
may be very important in grape regions where there is danger of early
frost to late-ripening sorts, and where it is often desirable to
retard the harvest time of early grapes.

In the behavior of the vines, the results correspond closely with
those given for yields. In the growth ratings of varieties on
different stocks, the varieties on their own roots were rated in vigor
at 40; on St. George, at 63.2; on Gloire, at 65.2; on Clevener, at
67.9. There is no way of deciding how much the thrift of the vines
depends on adaptability to soil, and how much on other factors. Since
all of the varieties were more productive and vigorous on grafted
vines than on their own roots it may be said that a high degree of
congeniality exists between the stocks and varieties under test.

The experiment suggests that it would be profitable to grow fancy
grapes of American species on grafted vines, and that it is well
within the bounds of possibility that main-crop grapes can be grafted
profitably. In the general tuning-up of agriculture now in progress,
it may be expected that soon American as well as European varieties of
grapes will be grown under some conditions and for some purposes on
roots other than their own.

DIRECT PRODUCERS

Attempts innumerable have been and are still being made to secure, by
hybridizing _V. vinifera_ and American species of grapes, varieties
that will resist phylloxera, the mildew and black-rot. The grapes of
this continent are relatively immune to all of these troubles, and if
hybrids could be obtained to produce directly, without grafting,
grapes with the good qualities of the Viniferas--in short, European
grapes on American vines--the cult