Watermelon (Citrullus lanatus (Thunb.), 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 (green, yellow and sometimes white) and a juicy, sweet interior flesh (usually pink, but sometimes orange, yellow, red and sometimes green if not ripe). It is also commonly used to make a variety of salads, most notably fruit salad.
Nutrition
A watermelon contains about 6% sugar and 92% water by weight. As with many other fruits, it is a source of vitamin C.
The amino-acid citrulline was first extracted from watermelon and analyzed. Watermelons contain a significant amount of citrulline and after consumption of several kg, an elevated concentration is measured in the blood plasma; this could be mistaken for citrullinaemia or other urea cycle disorders.
Watermelon rinds, usually a light green or white color, are also edible and contain many hidden nutrients, but most people avoid eating them due to their unappealing flavor. They are sometimes used as a vegetable. In China, they are stir-fried, stewed or more often pickled. When stir-fried, the de-skinned and de-fruited rind is cooked with olive oil, garlic, chili peppers, scallions, sugar and rum. Pickled watermelon rind is also commonly consumed in the Southern US. Watermelon juice can be made into wine.
Watermelon is mildly diuretic and contains large amounts of beta carotene. Watermelon with red flesh is a significant source of lycopene.
There are more than 1200 varieties of watermelon, ranging in weight from less than a pound to more than two hundred pounds, with flesh that is red, orange, yellow or white. The Carolina Cross produced the current world record watermelon weighing 262 pounds (119 kg). It has green skin, red flesh and commonly produces fruit between 65 and 150 pounds (29 and 68 kg). 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 pulp, 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 Volga River 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 25 lb (11 kg). The rind is black with no stripes or spots. It is grown only on the island of Hokkaido, Japan, where up to 10000 watermelons are produced every year. In June 2008, one of the first harvested watermelons was sold at an auction for 650 000 yen (6300 USD), making the most expensive watermelon ever sold. The average selling price is generally around 25 000 yen (250 USD).