At the beginning of
each summer it often takes a while for Tucson’s wild (and domestic) bees to
find the flowers in my garden. Often, during this time of year, I look around
my yard wondering where the bees are hiding and conclude that if I want my
vegetables pollinated then I will have to do it myself.
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| Male Melon Blossom - front view |
Members of the
Curbitaceae family (Cucumbers, Melons, and Squash) are monoecious. The Latin of
this name means “one house” and refers to the separation of the reproductive
parts of the plant into individual male and female flowers that grow on the
same plant. The technique of hand-pollinating monoecious vegetables is pretty
straight-forward. Here are some pictures to aid in hand pollinating melon
vines.
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| Male Melon Blossom - side view |
Before pollinating,
it is important to ensure that both male and female flowers in bloom. Male
flowers can be identified by the small short anthers with pollen in the middle
of the flower and the thin stem, devoid of bulging, leading up to the flower.
In contrast, female flowers exhibit a roundish folded stigma in the center of
the flower and a thicker immature shape which contains the unpollinated fruit.
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| A Female Melon Blossom with immature fruit (Left) |
Once the presence of
a male and female flower have been verified, then comes the pollinating itself.
With melon flowers I just pick the male flower, leaving as much stem as
possible attached, and pull back the petals to expose the anthers.
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| Pulling back the petals of the Male Blossom to expose the anthers |
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| Exposed Anthers of Male Blossom |
To pollinate, I
insert the male flower into the female flower just enough so that I can feel
that the male anthers just make contact with the female stigma. One technique I
found very effective to avoid damaging the female stigma is to gently rub the
male anthers around in the female flower to release the pollen. After
pollinating I then toss the male flower aside and hope for the best. If you desire
to increase chances that pollination will occur you can either pollinate again
with another male flower or you can wait until the next day to attempt the
process again. This will help you to overcome male pollen that is not viable or
a female flower that is not fully mature.
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| Pollinating Female Melon Blossom with male Anther |
In general, both male
and female flowers have a window of opportunity in which the bees (or people)
can complete the pollination process due to the limited timespan of male pollen
viability and female fruit receptivity. Male flowers lose their viability when
the flower petals turn a pale color and close, while unpollinated female
flowers are usually identified only after the fruit part of the stem turns
yellow wilts. In order to encourage consistent flower production, I regularly
remove any wilted fruit or pale flowers.
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| Female Melon blossoms progress (left to right): Immature, Pollinated, and Fruiting |
Pollinating your
plants may be necessary if you are growing in a greenhouse or if you need to
isolate a specific vegetable variety (cultivar) from another cultivar that you
are growing. If you are rouging or culling a specific variety for breeding
purposes, it is important to pollinate your own plants by selfing. Rather than
crossing plants using male and female flowers from different vines, selfing
isolates qualities of a specific plant by only pollinating female flowers with
male flowers of that specific plant. Once you have isolated the qualities of a
vegetable variety and produced seed, you can then replant that seed to create a
landrace (a large population of a variety that is adapted to your climate) by
crossing as many plants of the new variety as possible. The purpose of a
landrace is to keep future plants vigorous and strong by increasing genetic
variability within a given population. Lack of cross pollination within a
vegetable variety can weaken the variety and eventually lead to inbreeding depression.
So – why should a
gardener hand-pollinate their melons if there are no natural pollinators? To
watch as the female fruit grows.
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| A pollinated melon sets fruit and begins to grow. =) |
