Honey Bees are important pollinators
of vegetable crops requiring pollination for fruit and seed set, and
the activity of these insects can be the most limiting factor in watermelon
production. Watermelon requires insect pollination for fruit set.
Many watermelon growers rent honey bee colonies to ensure that maximum
fruit set and development occur.
Pistillate (or female) watermelon flowers require multiple bee visitations
after visting staminate (or male) flowers for adequate fruit set to
occur. Pollination is even more of a concern in triploid (seedless)
watermelon production since staminate flowers contain mostly nonviable
pollen. A standard diploid (or seeded) cultivar (hereafter refered
to as pollenizer) must be interplanted with a triploid cultivar as
a source of pollen to ensure that adequate fruit set occurs. It is
recommended that at least 20% pollenizer frequency be used to maximize
triploid watermelon production. However, to ensure that there is adequate
pollen available for fuit set, many growers use pollenizer frequencies
in the range of 25% to 33%.
There is limited information on triploid watermelon pollination. Generally,
studies have primarily delt with the influence of seeded pollenizers
on triploid watermelon yields. The objective of this research were
to determine the effects of honey bee pollination on fruit set, yield
and quality characteristics of triploid watermelon.
Six honey bee treatments - 1) no visitation control, 2) two visits,
3) four visits, 4) eight visits, 5) 16 visits, and 6) open-pollinated
control- were evaluated to determine the effectiveness of honey bee
pollination on ‘Millionare’ triploid watermelon fruit
set, yield, and quality utilizing ‘Crimson Sweet’ at a
33% pollenizer frequency. ‘Millionare’ quality characters
(hollow heart disorder or percent soluble solids) did not differ (P
greater than 0.05) between honey bee pollination treatments. The open-pollinated
control provided the highest fruit set rate (80%) and the greatest
triploid watermelon numbers and weights per plot compared to all other
honey bee visitation treatments. Fruit set, and fruit numbers and
weights per plot increased linearly as number of honey bee visists
to pistillate flowers increased from 0 (no visit control) to the open-pollinated
control (about 24 visits). This study indicated that between 16 and
24 honey bee visits are required to achieve maximum triploid watermelon
fruit set and yields at a 33% pollenizer frequency, which is twice
the number of honey bee visits required by seeded wateremelons to
achieve similar results. This is probably due to many honey bees visiting
staminate triploid watermelon flowers (that are in close proximity)
before visiting pistillate flowers thus providing mostly nonviable
pollen that is useless for fruit set and development. Therefore, more
honey bee visits to pistillate triploid watermelon flowers would be
required to achieve maximum fruit set and subsequent development compared
to seeded watemelons.
