Southeastern U.S. Vegetable Crop Handbook - 2022 - 130

VARIETIES1
AL
Triploid Mini/Seedless Mini
Extazy S
Leopard S
Mielheart S
Ocelot S
Paragon S
Sirius IR
1
A
Abbreviations for state where recommended.
2 Yellow flesh fruit.
3
Orange flesh fruit.
4 Local markets only.
A
MS
IR
S
G
Anthracnose tolerance/resistance.
Moderately susceptible to Fusarium wilt race 1.
Intermediate resistance to Fusarium wilt race 1.
Susceptible to Fusarium wilt race 1.
A
A
AR
GA
G
K
G
KY
LA
MS
NC
N
N
N
N
N
R
PM
OK
SC
S
TN
T
T
VA
V
S
S
Resistant to Fusarium wilt race 1.
Powdery mildew tolerance/resistance.
Seed Treatment. Check with seed supplier to determine if seed
has been treated with an insecticide or fungicide. Be sure that
seeds have been assayed for bacterial fruit blotch. Further information
on seed treatments can be found under SEED TREATMENTS
in the disease management section of the handbook.
Direct Seeding & Transplant Production.
Direct seeding for Diploids Only: Seed when the soil temperature
at the 4-inch depth is 60-65 °F. The recommended spacing
for watermelons, both direct seeded and transplant, is 6 - 12 feet
between rows providing 24 - 30 square feet per plant. Typically,
a wider row spacing will produce a larger-sized watermelon.
Transplant Production for Triploids: For seedless watermelons,
transplants should be grown in containers that provide a
space of at least 1.5 inches by 1.5 inches for each plant. Smaller
pots or cells will restrict root growth and provide less protection
to the newly set transplants. If the seed is of good quality with
high germination, one seed per pot is sufficient. The seed coat of
seedless watermelons tends to adhere to the seedling as it emerges,
at times slowing growth, or reducing stand.
For maximum germination, seedless watermelon seed
should be planted with the point of the seed facing up (root
end). However, this is not possible for any large-scale operation.
Growing media should be pre-watered and allowed to drain before
seeding and no additional moisture applied for at least 48
hours. Place trays in a germination chamber at 85-90°F for 48
hours. Next, place the trays in a greenhouse with day temperatures
70-80 °F and night temperatures 65-70°F.
The required amount of seed for direct seeding and transplant
production, the number of required seed can be estimated
using Table 6.
Planting. Transplants: Ideally, transplant container-grown
plants into plastic mulch after the last killing frost.
This is difficult
to predict and planting dates vary, so consult the following
table for your area. Plantings should be protected from winds
with row covers, rye strips, or windbreaks.
Grafting and Diseases. In recent years, grafted watermelon
plants have emerged as a strategy to combat soilborne diseases.
Grafting is used against Fusarium wilt. Grafted plants are more
expensive per transplant. For more information, see the section
Grafting in Vegetable Crops in this handbook.
130
POLLINATION AND PLANTING ARRANGEMENT
WITH TRIPLOIDS
Fruit set and enlargement in watermelon is dependent upon
growth regulators from pollen grains and from embryos in the
developing seeds within the fruit. Inadequate pollination results
in triploid watermelon fruit that are triangular in shape and of
inferior quality. Additionally, inadequate pollination increases
the incidence of hollow heart. Triploid watermelon flowers do
not produce viable pollen, which is required to induce fruit set
and development. Therefore, pollen from a " normal " (i.e., diploid/seeded)
or a special pollenizer watermelon variety must be
present.
Several seed companies have developed new varieties for
use solely as a pollenizer, non-edible special pollenizers. These
pollenizer can be interplanted into a field totally devoted towards
the production of triploid watermelons. Unique, compact growth
habits prevent these pollenizer from competing for space with
triploid plants.
Fields should be interplanted with pollenizer plants or diploid
watermelon plants in order to provide sufficient, viable pollen
for fruit set and development.
The arrangement for incorporating pollenizer plants in a
field of seedless watermelons has changed over the years. Currently
most growers plant the pollenizer plant between every
third and fourth plant within each row without changing the
plant spacing of the seedless/triploid watermelon. Due to the
less competitive nature of the special pollenizer plants mentioned
above, they often work best with this seedless/pollenizer
arrangement. However, growers can use a normal diploid/seeded
watermelon as a pollenizer. The diploid/seeded watermelon
must be marketable and have a fruit rind pattern and/or shape
easily distinguished from the seedless fruit. Not all diploid/seeded
watermelons are suitable for use as pollenizer due to excessive
plant vigor, reduced pollen production, and lack of disease
resistance. (See recommendations below for Edible Diploids).
It is also advisable that the grower reach an agreement with his
harvesting crew as to how both type watermelons will be handled
at harvest.
Many growers prefer special pollenizer because they do not
have markets for seeded watermelons. In addition, using a special
pollenizer makes harvesting easier for crews who can more
easily distinguish between fruit produced from the seeded, spe2022
Vegetable Crop Handbook for Southeastern United States
Southeastern U.S. Vegetable Crop Handbook - 2022

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