Hayes and Garber - Cucurbit Breeding

256 BREEDING CROP PLANTS
nucleus of Custard penetrated the ovary of Crookneck and took
up a position which, in many cases, was in close proximity to the
egg cell but for some reason fusion did not occur in most cases.
Bailey (1890), as the result of many artificial pollinations,
concludes "that the field pumpkins and the summer and fall
types of bush squashes (C. pepo) do not cross with the running
squashes of the Hubbard, Marblehead, Boston Marrow, turban,
and mammoth types (C. maxima}" In the Cyclopedia of
American Horticulture, Bailey (1900) states that C. moschata
and C. pepo may be crossed artificially but it is doubtful if
they cross naturally. Cucurbitacece in general are monoecious
and largely dependent on insects for pollination.
Immediate Effect of Pollination. There is a popular belief
widely disseminated that pumpkins and watermelons should
not be grown in close proximity to one another because of the
immediate effect of cross-pollination. A similar belief exists
with regard to cucumbers and muskmelons. Evidence accumulated
by various plant breeders shows that this idea is not founded
on fact. The work of Bailey at Cornell and Pammel at Iowa
may be cited. The former (1890) was unable to find any immediate
effect of cross-pollination between varieties of C. pepo and
likewise between varieties of C. maxima. Bailey not only was
unable to demonstrate any immediate effect of pollen in varieties
which could be crossed but he was even unable to produce crosses
between cucumbers and muskmelons. Ninety-seven flowers of
several varieties of melons were pollinated with different varieties
of cucumbers. Not a single fruit set. Twenty-five reciprocal
pollinations were also made. One fruit developed but produced
no seed. The setting of parthenocarpic fruit without fertilization
is not an infrequent occurrence in cucumbers. Pammel (1892),
in an intermingled planting of varieties of each of the following
species, Citrullus vulgaris, Cucumis melo, Cucurbita maxima,
Cucumis sativus, and Cucurbita pepo provided excellent facilities
for inter-specific pollinations. Neither the watermelons nor the
muskmelons showed contamination. Some hand pollinations between
species were made, but no cross-fertilization was obtained.
The variability in flavor of commercial varieties of melons is
undoubtedly partly responsible
for the erroneous belief that
they may be contaminated by other species of cucurbits growing
in close proximity. At the Connecticut Station an extensive
varietal test was made. Most of the varieties were of
very inferior quality even though they were exposed only to