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Watermelon

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The watermelon, scientifically known as Citrullus lanatus, is a flowering plant in the Cucurbitaceae family. It is famous for producing a large, edible fruit that is highly valued for its water content.

Watermelon seedless
Watermelon seedless

Botanically, the watermelon is classified as a pepo. A pepo is a type of modified berry characterized by a thick, hard outer rind called an exocarp. Inside this rind, the fleshy part consists of the mesocarp and endocarp. This fruit is widely cultivated in both tropical and temperate climates across the globe. With more than 1,000 varieties existing, it is one of the most diverse food crops in the world.

Growing a watermelon involves a specific biological process. The plant is an annual that grows as a trailing or climbing vine. It features stems that can reach significant lengths and new growth covered in yellow or brown hairs. The leaves are large and typically have three lobes. Most watermelon plants are monoecious, meaning they produce both male and female flowers on the same plant.

At the start of the season, male flowers are more common. Later, female flowers develop and possess inferior ovaries. For commercial growers, pollination is a critical step. For seeded varieties, the USDA recommends at least one beehive per acre. However, seedless hybrids require more help because they have sterile pollen. Farmers must plant extra rows of pollinizer varieties and use up to three beehives per acre to ensure success.

There are several distinct types and groups of watermelon. One group is the Citroides group, which includes the citron melon, or makataan. This variety has sweet yellow flesh and is used for pectin or as animal fodder. Another significant group is the Lanatus group. Within these classifications, the bitter wooly melon, Citrullus lanatus var. lanatus, is a known variety.

Citrullus lanatus afghan melon
Citrullus lanatus afghan melon

There is also the edible variety, C. lanatus var. vulgaris, which is likely the most important for human consumption. While most modern watermelons have red or pink flesh, some varieties can be orange, yellow, green, or white. Some even produce seedless fruit, which became popular in the 21st century.

The history of the watermelon is rooted in Africa. Evidence suggests that the Kordofan melon from Sudan may be the ancestor of modern watermelons.

Pasteques, extrait d'un tableau de Giovanni Stanchi
Pasteques, extrait d'un tableau de Giovanni Stanchi

Archaeologists found wild watermelon seeds at a prehistoric site in Libya called Uan Muhuggiag, dating to approximately 3500 BC. A 2022 study even traced these 6,000-year-old seeds to the Egusi seeds of Nigeria. By 2000 BC, watermelons were being cultivated in Egypt. Early versions were not the sweet fruits we know today; they were often bitter with yellowish-white flesh. Through centuries of selective breeding, humans developed the sweet, easy-to-open varieties used in modern agriculture.

Taxonomy, or the science of naming organisms, has evolved significantly for this plant. Carl Linnaeus first described the sweet watermelon in 1753 as Cucurbita citrullus. In 1836, the German botanist Heinrich Adolf Schrader reassigned it to the genus Citrullus, calling it Citrullus vulgaris.

Later, L.H. Bailey mistakenly grouped the wooly melon with the sweet watermelon in 1930. Modern molecular data has corrected this, proving they are not closely related. This led to the formal acceptance of the name Citrullus lanatus by the International Botanical Congress in 2017.

Watermelon production is a massive global industry. In 2023, the world produced 105 million tonnes of watermelon. China is the dominant leader, producing 64% of the total global supply.

Albert Eckhout 1610-1666 Brazilian fruits
Albert Eckhout 1610-1666 Brazilian fruits

Other major producers include India, Turkey, Algeria, and Brazil. The fruit is highly nutritious and efficient for hydration. It is composed of 91% water and 6% sugars. The pulp also contains carotenoids, such as lycopene, which gives many watermelons their deep red color. The rind is also useful, as it contains the amino acid citrulline.

Beyond food, watermelons play vital roles in different ecosystems and cultures. In arid regions like the Kalahari Desert and East Africa, they serve as a crucial water source for both humans and animals. Cultivation requires specific environmental conditions, such as well-drained sandy loam with a pH between 5.7 and 7.2.

Watermelon seedless
Watermelon seedless

If pollination is insufficient, a condition called "hollow heart" can occur. This creates a large, symmetric hole in the center of the flesh, though the fruit remains safe to eat. From ancient Egyptian tombs to modern supermarkets, the watermelon remains a globally significant crop.

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🖼️ Images & Media (5)
File:Citrullus lanatus afghan melon.jpg
Citrullus lanatus afghan melon.jpg
File:Albert Eckhout 1610-1666 Brazilian fruits.jpg
Albert Eckhout 1610-1666 Brazilian fruits.jpg
File:Leiden University Library - Seikei Zusetsu vol. 27, page 018 - 西瓜 - Citrullus lanatus (Thunb.) Matsum. & Nakai - Cucurbita maxima Duchesne, 1804.jpg
Leiden University Library - Seikei...
File:Watermelon seedless.jpg
Watermelon seedless.jpg
File:Pasteques, extrait d'un tableau de Giovanni Stanchi.jpeg
Pasteques, extrait d'un tableau de...
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