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HORT410 - Vegetable Crops

Watermelon - Notes

  • Common name: watermelon.
  • Latin name: Citrullus lanatus (Thunberg) Matsumara & Nakai (also called C. vulgaris).
  • Family name: Cucurbitaceae [Cucurbitaceae Images].
  • Annual.
  • Dicotyledon.
  • Trailing vine.
  • Diploid (2n = 22) [but note that some cultivars are tetraploid, and seedless watermelons are triploid].
  • Pollinated by bees.
  • Harvested organ: large fruits.
  • Fruits have a hard rind and a soft, sweet-fleshed interior when ripe.
  • Origin: native to Africa; introduced into N. America during the 16th century.
  • Watermelon history (TAMU).
  • Warm season, frost suceptible.
  • Number of fruits per vine varies from 2 to 15.
  • Weight of each watermelon ranges from 3 lb to 50 lb.
  • Flesh color variable: red, pink, yellow, or white.
  • Monoecious and andromonoecious types of flowering habits; monoecious most common.
  • F1 hybrid watermelons becoming increasingly popular; the production scheme is similar to maize [plants of the maternal and paternal parents are grown in alternate rows; male flowers in maternal rows are removed by hand in the early morning when insects are not present; female flowers in these rows receive only pollen from the paternal parent].
  • Most cultivars are diploid, but triploids and tetraploids are becoming increasingly important.
  • Triploid watermelons produced from the cross of tetraploid and diploid forms; the triploid hybrids are almost seedless.
  • Watermelons reach maturity approximately 45 days after blooming; highly dependent upon cultivar.
  • Typically harvested when the tendril nearest the melon is wilting and the ground spot has turned from white to yellow.
  • Immature watermelons have turgid tendrils; a completely wilted tendril can be indicative of over-maturity.
  • Fruit is rich in sugar (soluble solids); a sugar content of 17% is considered excellent quality.
  • Other indicators of ripe fruit include ridges on the rind surface, and a hollow or dull sound when "thumped".
  • Fruit should be cut cleanly from the vine to avoid stem damage and prevent stem-end rot.
  • Fruit is chilling sensitive and should not be stored below 7 C; optimum storage temperatures are 7 to 10 C.
  • Major diseases of watermelons in the Midwest:
  • Major insect pests of watermelons in the Midwest:
  • Cucumber beetles are of lesser concern to watermelon growers than cucumber and muskmelon growers because watermelon is not susceptible to bacterial wilt.
  • Protection of watermelons from cucumber beetles is necessary when plants are small and high beetle populations are feeding on stems, or when beetles are feeding on the fruit.
  • Careful when applying pesticides that are toxic to honey bees during flowering; can decrease pollination and fruit set.

    (see: ID-56: Midwest Vegetable Production Guide for Commercial Growers 2003 - Cucumber, Muskmelon, and Watermelon (PURDUE) [pdf] for watermelon crop recommendations (varieties, spacing, fertilizing, irrigation, harvesting, disease, weed and insect control) for the Midwest)

    Sources of information:

  • Foster, R., Brust, G., Barrett, B. Watermelons, muskmelons, and cucumbers. In "Vegetable Insect Management With Emphasis on the Midwest", (ed. R. Foster, B. Flood), Meister Publishing Co., Willoughby, Ohio, pp. 157 - 168 (1995).
  • Nonnecke, I.L. "Vegetable Production", Van Nostrand Reinhold, NY (1989).
  • Phillips, R., Rix, M. "The Random House Book of Vegetables", Random House, NY (1993).
  • Hall, C.V. Watermelon. In "The Software Toolworks Multimedia Encyclopedia", Version 1.5, Grolier, Inc. (1992).
  • Feher, T. Watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai. In "Genetic Improvement of Vegetable Crops", (ed. G. Kalloo, B.O. Bergh), Pergamon Press, Oxford, U.K., pp. 295-311 (1993).
  • Midwest Vegetable Production Guide for Commercial Growers, ID-56, eds. R. Foster, D. Egel, E. Maynard, R. Weinzierl, H. Taber, L.W. Jett, B. Hutchinson, Purdue University Cooperative Extension Service, 2003.
  • Musmade, A.M., Desai, U.T. Cucumber and melon. In "Handbook of Vegetable Science and Technology: Production, Composition, Storage, and Processing", (ed. D.K. Salunkhe, S.S. Kadam), Marcel Dekker, Inc., NY, pp. 245-272 (1998).

    www www.hort.purdue.edu
  • David Rhodes
    Department of Horticulture & Landscape Architecture
    Horticulture Building
    625 Agriculture Mall Drive
    Purdue University
    West Lafayette, IN 47907-2010
    Last Update: 01/07/08