Seedless triploid watermelons provide the same nutrients as watermelons with seeds. Because seedless varieties can put all their energy into fruit development, these plants can yield melons with better flavor and higher sugar content than seeded types. Actual melon quality varies with cultivation practices. The intensive greenhouse production of seedless melons grown for the winter market often produces watermelons that fall short in flavor and nutritional value.
Size
Seedless watermelons commonly weigh 15 to 20 pounds. Smaller icebox watermelons such as the Honey Heart weigh 6 to 10 pounds each. The rind, seeds and lost juice account for about half the weight of the average seeded melon. Seedless varieties yield a higher percentage of edible flesh, but the amount varies with the stage of ripeness and the thickness of the rind. About half the sugar in watermelon is fructose, while sucrose and glucose account for about 25 percent each. A 10-pound melon that's 6 percent sugar has about 1,350 calories.
Nutrients
Almost 92 percent of a watermelon’s weight is water. The carbohydrates in watermelons are primarily of sugar, but a 10-pound melon also has 18 grams of of dietary fiber. A 1 2/3-cup serving of watermelon provides almost half your daily requirement of vitamin C and about twice your daily minimum of potassium. This serving also has your entire day’s supply of vitamin A. Ripe watermelons contribute high amounts of lycopene, an anti-oxidant that helps to prevent cardiovascular disease and cancer. Only tomatoes have more lycopene than watermelon, according to the the University of Illinois Extension. The lutein and zeaxanthin in watermelons protect your vision by shielding eye tissue from harmful ultraviolet light.
Variability
The amount of nutrients in individual watermelons vary. When insects or disease attack watermelon leaves, the fruits have less sugar and other nutrients. Growing environments also affect fruit quality. In good soil, a watermelon vine grown by traditional methods could produce fruit with a sugar content as high as 14 percent, according to organic farmer Bob Omlor of Darlington, Pa. Omlor tested commercial melons and found sugar content of only 4 to 6 percent. A seedless watermelon that isn't sweet could have been harvested early or grown out-of-season in a greenhouse.
Origins
Development of the seedless watermelon began in 1939, according to Todd Wehner of North Carolina State University. Chemical treatment of young watermelon plants from standard varieties created a few plants with four sets of chromosomes instead of the normal two sets. Crossing these plants with normal diploids yielded a new triploid seedless variety. Current seedless watermelon varieties meet high standards of potential nutritional quality. Any watermelon with pale tasteless flesh lacks both lycopene and sugar and won't match the nutritional quality of a fully ripe melon from a healthy plant.
References
- University of Illinois Extension: Watermelon
- USDA National Nutrient Database: Search -- Watermelon
- Pittsburgh Post-Gazett; On the Menu: When It Comes to Watermelon, the Flavor has Disappeared Along with the Seeds; China Millman; August 2008
- North Carolina State University; Watermelon Crop Information -- Breeding Methods; Todd C. Wehner; September 1996
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