July
2005
By
B. Rosie Lerner
Extension Consumer Horticulturist
Purdue University
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Squashkins and Cucumelons?
As you plant out your vegetable transplants and seeds in the garden,
have you ever wondered what happens if you grow a zucchini squash next
to a giant pumpkin? Do you end up with squashkins? Will planting cucumbers
next to watermelons yield cucumelons?
These two examples are not likely to cross-pollinate one another, so the
answer is probably "no." Plants of different species usually
do not cross-pollinate in nature. Cross-pollination does frequently take
place among some of the winter squash, pumpkins and gourds that are closely
related. But the results of such a cross would not be evident in this
year's fruit.
To further explain, we must first discuss a little botany. The fruit of
any plant is actually a mature ovary, botanically speaking. The seed inside
is similar to a child while the fruit is analogous to the mother. The
seed, or child, has characteristics of both parents. The fruit remains
whatever the mother plant was to begin with. In other words, if cross-pollination
did take place, the seed, not the fruit, would be result of that cross.
The seed would have to be harvested, stored and planted out the following
year to determine if cross-pollination had an effect. Then, the resulting
fruit on those plants might look like a combination of both parents.
If you do turn up some unexpectedly odd-looking fruits in your squash
patch, it is possible that the seed packet contained a few seeds that
were of questionable parentage. However, it is more likely that a "volunteer"
squash from last year's garden is the culprit.
Corn is the exception to the rule; cross-pollination does affect this
year's corn crop. In this case, the kernel of corn is both seed and fruit
at the same time. So the outcome of cross-pollination in corn can be dramatically
obvious. Yellow color in corn is dominant over white, so a white variety
that gets pollinated by a yellow variety will have some kernels of each
color (called bi-colored). Starchy field corn or popcorn is dominant over
sweet corn. So sweet corn that gets some stray pollen from field corn
will have some kernels that are starchy. Each kernel is the result of
a separate pollination incident, so if only a small amount of contaminating
pollen is at work, the result in flavor might not be noticed in a mouthful
of otherwise sweet kernels.
7-7-05
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