Watermelon growers
are currently shifting from seeded (diploid) to seedless (triploid)
production due to increased consumer demand and a greater economic profit
obtained from growing seedless watermelons. Seedless watermelons do
not produce sufficient pollen to fertilize female flowers and require
specialized cultural practices, compared to seeded watermelons, to produce
adequate yields. A standard seed producing cultivar (hereafter referred
to as a pollinizer) must be interplanted with a seedless cultivar as
a source of pollen
.
Little research has been published on the influence of seeded pollinizer
frequencies on seedless watermelon yield and quality. For field production
of seedless watermelons some research has suggested that one diploid
plant should be planted for every four to five triploid plants to ensure
that the triploids would produce adequate fruit yield.
Other studies have shown that the greatest yield of ‘Genesis’
triploid watermelon with ‘Ferarri’ as the pollinizer resulted
from a 20% pollinizer frequency. Currently it is recommended that one
row of pollinizer be planted for every two or four rows of seedless
watermelon to provide adequate pollen for fruit set. It is essential
to select a pollinizer that is easily distinguishable from the seedless
cultivar for ease of harvesting and marketing purposes.
Additional research is needed to determine the optimal frequency of
pollenizers needed under field conditions to obtain maximum yields in
seedless watermelon production. Use of the minimum pollinizer frequency
needed to maximize seedless watermelon yields could expand the profit
margins for growers. Pollinizers are important to seedless watermelon
production, and more studies are needed to obtain information about
the effects of pollinizers on seedless watermelon quality and yield.
Hollow heart, a hollow area that develops from splitting of the interior
flesh of watermelon, is a serious quality problem in seedless watermelon
production and could be related to pollen source. Knowledge of the best
pollenizers and appropriate seedless-topollenizer ratios could possibly
improve watermelon quality and yield. The objectives of this research
were to determine the influence of pollenizer and pollenizer frequency
on ‘Millionare’ seedless watermelon quality and yield.
During the 1999 abd 2000 growing seasons in Illinois, studies were conducted
to determine the infuence of two pollenizers (‘Crimson Sweet’
and ‘Fiesta’) and three pollenizer frequencies (11%, 20%,
and 33%) on ‘Millionare seedless watermelon (Citrullus lanatus)
quality and yields. More large-sized [>16 lb (7.2 kg)] ‘Millionare’
watermelons were produced when ‘Crimson Sweet’ was used
as the pollinizer compared to ‘Fiesta’, which resulted in
‘Crimson Sweet’ leading to greater marketable and total
‘Millionare’ yields. Pollinizers responded similarly over
the pollinizer frequencies for ‘Millionare’ watermelon yields
as no pollinizers by pollenizer frequency interaction was observed.
The 20% and 33% pollinizer frequencies produced similar ‘Millionare’
yields per acre and both resulted in greater yields compared to the
11% pollinizer frequency. Soluble solids in ‘Millionare’
fruits were not influenced by pollinizer or pollinizer frequency. However,
hollow heart disorder followed a quadratic response with respect to
pollinizer frequency with the lowest amount of hollow heart observed
at the 33% pollinizer frequency and greatest at the 11% pollinizer frequency.
No significant interaction (P< 0.05) was observed for pollinizer
by pollinizer frequency for hollow heart disorder in ‘Millionare’;
although, more hollow heart disorder in ‘Millionare’ was
observed when ‘Fiesta’ was used as the pollinizer.
