|Citrullus lanatus var. lanatus
(Thunb.) Matsum. & Nakai
|Watermelon output in 2005|
Watermelon (Citrullus lanatus var. lanatus, family Cucurbitaceae) is a vine-like (scrambler and trailer) flowering plant originally from southern Africa. Its fruit, which is also called watermelon, is a special kind referred to by botanists as a pepo, a berry which has a thick rind (exocarp) and fleshy center (mesocarp and endocarp). Pepos are derived from an inferior ovary, and are characteristic of the Cucurbitaceae. The watermelon fruit, loosely considered a type of melon – although not in the genus Cucumis – has a smooth exterior rind (usually green with dark green stripes or yellow spots) and a juicy, sweet interior flesh (usually deep red to pink, but sometimes orange, yellow, or white).
Watermelon is thought to have originated in southern Africa, where it is found growing wild. It reaches maximum genetic diversity there, with sweet, bland and bitter forms. In the 19th century, Alphonse de Candolle considered the watermelon to be indigenous to tropical Africa. Though Citrullus colocynthis is often considered to be a wild ancestor of watermelon and is now found native in north and west Africa, it has been suggested on the basis of chloroplast DNA investigations that the cultivated and wild watermelon diverged independently from a common ancestor, possibly C. ecirrhosus from Namibia.
Evidence of its cultivation in the Nile Valley was found from the second millennium BC. Watermelon seeds have been found at Twelfth Dynasty sites and in the tomb of Pharaoh Tutankhamun. Watermelon is also mentioned in the Bible as a food eaten by the ancient Israelites while they were in bondage in Egypt.
By the 10th century, watermelons were being cultivated in China, which is today the world's single largest watermelon producer. By the 13th century, Moorish invaders had introduced the fruit to Europe; according to John Mariani's Dictionary of American Food and Drink, "watermelon" made its first appearance in an English dictionary in 1615.
Watermelons were grown by Native Americans in the 16th century. Early French explorers found the fruit being cultivated in the Mississippi Valley. Many sources list the watermelon as being introduced in Massachusetts as early as 1629. Southern food historian John Egerton has said he believes African slaves helped introduce the watermelon to the United States. Texas Agricultural Extension horticulturalist Jerry Parsons lists African slaves and European colonists as having distributed watermelons to many areas of the world. Parsons also mentions the crop being farmed by Native Americans in Florida (by 1664) and the Colorado River area (by 1799). Other early watermelon sightings include the Midwestern states (1673), Connecticut (1747) and the Illiana region (1822).
Charles Fredric Andrus, a horticulturist at the USDA Vegetable Breeding Laboratory in Charleston, South Carolina, set out to produce a disease-resistant and wilt-resistant watermelon. The result, in 1954, was "that gray melon from Charleston". Its oblong shape and hard rind made it easy to stack and ship. Its adaptability meant it could be grown over a wide geographical area. It produced high yields and was resistant to the most serious watermelon diseases: anthracnose and fusarium wilt.
Today, farmers in approximately 44 states in the US grow watermelon commercially, and almost all these varieties have some 'Charleston Gray' in their lineage. Georgia, Florida, Texas, California and Arizona are the US's largest watermelon producers. This now-common watermelon is often large enough that groceries often sell half or quarter melons. Some smaller, spherical varieties of watermelon, both red- and yellow-fleshed, are sometimes called "icebox melons".
|Top five watermelon producers (2012, in tonnes)|
For commercial plantings, one beehive per acre (4,000 m2 per hive) is the minimum recommendation by the US Department of Agriculture for pollination of conventional, seeded varieties. Because seedless hybrids have sterile pollen, pollinizer rows of varieties with viable pollen must also be planted. Since the supply of viable pollen is reduced and pollination is much more critical in producing the seedless variety, the recommended number of hives per acre, or pollinator density, increases to three hives per acre (1,300 m2 per hive). Watermelons have a longer growing period than other garden plants and can often take up to 85 days of growing to mature.
In Japan, farmers of the Zentsuji region found a way to grow cubic watermelons, by growing the fruits in glass boxes and letting them naturally assume the shape of the receptacle. The cubic shape was originally designed to make the melons easier to stack and store, but the cubic watermelons are often more than double the price of normal ones, and much of their appeal to consumers is in their novelty. Pyramid-shaped watermelons have also been developed and any polyhedral shape may potentially also be used. These shaped watermelon are often harvested before optimal ripeness. Because they are bitter instead of sweet, the shaped fruits are considered ornamental instead of food. 
The amino-acid citrulline was first extracted from watermelon and analyzed. Watermelons contain a significant amount of citrulline and after consumption of several kilograms, an elevated concentration is measured in the blood plasma; this could be mistaken for citrullinaemia or other urea cycle disorders.
Watermelon rinds are also edible, but most people avoid eating them due to their unappealing flavor. They are used for making pickles, and sometimes used as a vegetable.[better source needed] In China, they are stir-fried, stewed or more often pickled. Pickled watermelon rind is sometimes eaten in the Southern US.[better source needed] Watermelon juice can be made into wine.[better source needed]
Watermelon is mildly diuretic and contains large amounts of carotenoids. Watermelon with red flesh is a significant source of lycopene. Preliminary research indicates the consumption of watermelon may have antihypertensive effects.
- The 'Carolina Cross' produced the current world record watermelon weighing 120 kilograms (260 lb). It has green skin, red flesh and commonly produces fruit between 29 and 68 kilograms (65 and 150 lb). It takes about 90 days from planting to harvest.
- The 'Yellow Crimson' has a yellow-colored flesh. It has been described as sweeter and more honey-flavored than the more popular red-flesh watermelon.
- The 'Orangeglo' has a very sweet orange flesh, and is a large, oblong fruit weighing 9–14 kg (20–30 pounds). It has a light green rind with jagged dark green stripes. It takes about 90–100 days from planting to harvest.
- The 'Moon and Stars' variety was created in 1926. The rind is purple/black and has many small, yellow circles (stars) and one or two large, yellow circles (moon). The melon weighs 9–23 kg (20–50 pounds). The flesh is pink or red and has brown seeds. The foliage is also spotted. The time from planting to harvest is about 90 days.
- The 'Cream of Saskatchewan' consists of small, round fruits around 25 cm (10 inches) in diameter. It has a quite thin, light green with dark green striped rind, with sweet white flesh and black seeds. It can grow well in cool climates. It was originally brought to Saskatchewan, Canada, by Russian immigrants. The melon takes 80–85 days from planting to harvest.
- The 'Melitopolski' has small, round fruits roughly 28–30 cm (11–12 inches) in diameter. It is an early ripening variety that originated from the Astrakhan region of Russia, an area known for cultivation of watermelons. The Melitopolski watermelons are seen piled high by vendors in Moscow in summer. This variety takes around 95 days from planting to harvest.
- The 'Densuke' watermelon has round fruit up to 11 kg (24 lb). The rind is black with no stripes or spots. It is grown only on the island of Hokkaido, Japan, where up to 10,000 watermelons are produced every year. In June 2008, one of the first harvested watermelons was sold at an auction for 650,000 yen (US$ 6,300), making it the most expensive watermelon ever sold. The average selling price is generally around 25,000 yen ($ 250).
- Many cultivars are no longer grown commercially because of their thick rind, but seeds may be available among home gardeners and specialty seed companies. Old cultivars with good flavour and other features, as well as the thick rind desirable for making watermelon pickles include 'Tom Watson', 'Georgia Rattlesnake', and 'Black Diamond'.
- The citrulline in watermelon (especially in the rind) is a known stimulator of nitric oxide. Nitric oxide is thought to relax and expand blood vessels, much like the erectile dysfunction drug Viagra, and may even increase libido.
- Fans of the Saskatchewan Roughriders of the CFL started a tradition of hollowing out a watermelon and wearing it as a makeshift football helmet (the color of the Roughriders is green). During the 2009 Grey Cup in Calgary (between the Montreal Alouettes and the Roughriders), thousands of watermelons had to be imported to Calgary supermarkets to prevent a shortage being caused by Rider fans.
- It is the symbol of the Turkish city, Diyarbakır.
- The Oklahoma State Senate passed a bill on 17 April 2007 declaring watermelon as the official state vegetable, with some controversy surrounding whether a watermelon is a vegetable or a fruit.
- The ten-lined June beetle is often affectionately referred to as a watermelon beetle, due to the green, striped pattern on its back.
- In U.S. culture, stereotypical caricatures may depict African Americans as being inordinately fond of watermelon (along with fried chicken), to the point where some African Americans do not want to be seen in public eating watermelon.[page needed]
- In Vietnamese culture, watermelon seeds are consumed during the Vietnamese New Year's holiday, Tết, as a snack.
Flower stems of male and female watermelon blossoms, showing ovary on the female
Seeds of many watermelon varieties, packed in little cans, sold to farmers in the seed-shop district of Wuhan, China
- Citron melon, the ancestral form of watermelon
- List of fruits
- Vampire pumpkins and watermelons
- Watermelon seed oil
- Watermelon steak
- Candolle, Origin of Cultivated Plants (1882) pp 262ff, s.v. "Water-melon".
- Wehner, Todd C. Watermelon Crop Information. North Carolina State University
- Dane, Fenny; Liu, Jiarong (2006). "Diversity and origin of cultivated and citron type watermelon (Citrullus lanatus)". Genetic Resources and Crop Evolution 54 (6): 1255. doi:10.1007/s10722-006-9107-3.
- Zohary, Daniel and Hopf, Maria (2000) Domestication of Plants in the Old World, third edition, Oxford University Press, p. 193, ISBN 0198503571.
- Freedman, David Noel and Myers, Allen C. (2000). Eerdmans Dictionary of the Bible. Amsterdam University Press. pp. 1063–. ISBN 978-90-5356-503-2.
- "Watermelon developer dies at 101". Post and Courier, 16 July 2007
- "Statistics from: Food And Agricultural Organization of United Nations: Economic And Social Department: The Statistical Division". UN Food and Agriculture Organization Corporate Statistical Database.
- Square fruit stuns Japanese shoppers. BBC News, 15 June 2001.
- "Square watermelons Japan. English version". YouTube. 2013-11-06. Retrieved 2014-08-03.
- Wada, M. (1930). "Über Citrullin, eine neue Aminosäure im Presssaft der Wassermelone, Citrullus vulgaris Schrad". Biochem. Zeit. 224: 420.
- Mandel, H.; Levy, N.; Izkovitch, S. and Korman, S. H. (2005). "Elevated plasma citrulline and arginine due to consumption of Citrullus vulgaris (watermelon)". Berichte der deutschen chemischen Gesellschaft 28 (4): 467–472. doi:10.1007/s10545-005-0467-1. PMID 15902549.
- Todd C. Wehner (2008). "12. Watermelon". In Jaime Prohens and Fernando Nuez. Handbook of plant breeding. Volume 1, Vegetables. I, Asteraceae, Brassicaceae, Chenopodicaceae, and Cucurbitaceae. Springer. pp. 381–418.
- "Watermelon Rind Stir-Fry". Retrieved 27 April 2013.
- Rattray, Diana (30 January 2012). "Southern U.S. Cuisine: Judy's Pickled Watermelon Rind". Southernfood.about.com. Retrieved 13 February 2012.
- Watermelon Wines. winemaking.jackkeller.net
- The Associated Press (3 July 2008). "CBC News – Health – Watermelon the real passion fruit?". CBC. Retrieved 3 August 2014.
- "HowStuffWorks "Health Benefits of Watermelon"". HowStuffWorks. Retrieved 5 December 2009.
- Figueroa A, Sanchez-Gonzalez MA, Wong A, Arjmandi BH (2012). "Watermelon extract supplementation reduces ankle blood pressure and carotid augmentation index in obese adults with prehypertension or hypertension". American journal of hypertension 25 (6): 640–3. doi:10.1038/ajh.2012.20. PMID 22402472.
- "Vegetable Research & Extension Center – Icebox Watermelons". Retrieved 2008-08-02.
- "Watermelons". Annie's Heirloom Seeds. Retrieved 2011-08-24.
- "Orangeglo Watermelon". Archived from the original on 2007-09-27. Retrieved 2007-04-23.
- "Moon and Stars Watermelon Heirloom". rareseeds.com. Archived from the original on 2007-12-17. Retrieved 2008-07-15.
- Evans, Lynette (2005-07-15). "Moon & Stars watermelon (Citrullus lanatus) — Seed-spittin' melons makin' a comeback". The San Francisco Chronicle. Archived from the original on 2007-10-13. Retrieved 2007-07-06.
- "Moon and Stars Watermelon". Archived from the original on 2007-06-02. Retrieved 2007-04-23.
- "Watermelon, Cream Saskatchewan". seedsavers.org. Archived from the original on 2009-02-21.
- "Melitopolski Watermelon". Archived from the original on 2007-09-27. Retrieved 2007-04-23.
- Hosaka, Tomoko A. (6 June 2008). "Black Japanese watermelon sold at record price". The Associated Pres. Archived from the original on 2008-06-09. Retrieved 2008-06-10.
- "Watermelon May Have Viagra-effect". Science Daily. 1 July 2008. Retrieved 5 December 2009.
- Watermelon shortage averted[dead link]. CBC News. 27 November 2009.
- "Oklahoma Declares Watermelon Its State Vegetable". CBS4denver. 18 April 2007. Archived from the original on 2008-03-02. Retrieved 3 October 2009.
- Brown, Joshua (2006). Beyond the Lines: Pictorial Reporting, Everyday Life, And the Crisis of Gilded Age America. University of California Press, p. 284, ISBN 0520248147.
- The Asian Texans By Marilyn Dell Brady, Texas A&M University Press
|Wikispecies has information related to: Citrullus vulgaris|
- Media related to Citrullus lanatus at Wikimedia Commons
- The dictionary definition of watermelon at Wiktionary