Agriculture Reference
In-Depth Information
SELECTION CHARACTERISTICS
Watermelon varieties differ in the color of the flesh, the size and
shape of the fruit, and the color and pattern of the rind. Seeds are, again depending on the variety,
black, brown, red, green, or white. Potential selection criteria:
• earliness
• plant health
• number of fruits per plant
• flavor (especially sweetness) of fruit
DISEASES AND PESTS
Watermelons are grown with relative ease only in hot climates and are more
susceptible to fungal diseases in wetter climates. Fusarium rot (
Fusarium roseum
) is not seed-borne
but is often found in the soil and on plant debris. Yellowish brown spots are usually seen on ripe or
near-ripe fruits. Prevention: keeping fruits off of wet soil, crop rotation of at least three years. Bacterial
speck disease is caused by the bacteria
Pseudomonas syringae
and can be seed- or soil-borne. This is
the main bacterial disease where watermelons are grown on a large scale. Use at least a four-year crop
rotation to help prevent bacterial speck. Viral diseases can also be a problem in watermelon cultiva-
tion, causing spots and checkered patterns on young leaves and stunted growth. Remove plants with
viral infections.
Citrons, melon and otherwise
A lesser-known member of the species is the citron melon (
Citrullus lanatus
var.
citroides
).
Citron melon is not eaten fresh like the watermelon but rather is pickled, candied, or made into
jams and jellies. The citron is a citrus crop (
Citrus medica
var.
medica
).
CULTIVATION HISTORY
Wild forms of watermelon are densely hairy vines with small, bitter fruits;
they grow in the Kalahari Desert of Namibia and in southern Africa. The watermelon was an important
fruit in ancient Egypt, with the earliest evidence from around 2000
BC
. It quickly spread to India and
China, where the desert watermelon was bred. The desert watermelon was then brought back west by
Arabs. In Africa, the oil- and protein-rich seeds are eaten raw; in India, seeds are ground and baked in-
to a kind of bread; in the Far East, the seeds are roasted. Large-seeded varieties have been bred in Ch-
ina for just this purpose (roasting); hybridizers in Japan have been working in the other direction,
breeding varieties with small seeds, so as not to interfere with consumption of the fruit's flesh. Seed-
less hybrids first started appearing in the 1950s.
