An Article about Watermelon Seeds

Some of the different pulp varieties. Source: NCSU

Watermelon (Citrullus lanatus) originates from southern Africa and is believed to have been domesticated at least 4,000 years ago. In 2009, world production of watermelon totaled about 98 million metric tons (FAOSTAT). "Fruits vary considerably in morphology. Whereas the fruits of the wild Kalahari form are small and round, the cultivated forms are large oblong fruits. In addition, they vary from pale yellow or light green (wild form) to dark green (cultivars), and with or without stripes; the pulp varies from yellow or green (wild forms) to dark red (cultivars) (Jeffrey 1978)."

Diversity in watermelon fruit shape and color. Source: NCSU

The following article, published in Slate, explains why the watermelon variety most commonly eaten in the U.S. has white and black seeds.

What's With White Watermelon Seeds?  

(Read after the break)

 

 What's With White Watermelon Seeds? 

They're just immature.

By Brahna Siegelberg 
Posted Friday, July 29, 2011, at 12:03 PM ET
What's with the different-colored seeds?Watermelons, as anyone who's ever eaten one has likely noticed, contain both small white seeds and larger black ones. Seeing as it's watermelon season, the Explainer thought she'd answer the terribly pressing question: What's the difference between the seeds?

Maturity. All watermelon seeds start off small and white before growing into larger black, red, tan, or dotted seeds. (More on these less-familiar colors later.) The average American watermelon has about 200 to 800 seeds, and roughly 5 percent of those are still immature upon harvest. These seeds are infertile, so unlike their black cousins, you can't use them to plant your own crop of watermelons.

Undeveloped seeds should not be confused with seeds from white-seeded watermelons, which are very common in China and the Middle East (not so much here). American farmers tend to produce watermelons of the black-seeded variety for aesthetic reasons, but watermelons have a vast array of gene combinations that can produce a variety of seed, rind, and flesh colors.

Along with squash, cucumber, cantaloupe, and pumpkin, watermelons are members of the cucurbit family, which produce fruits called "pepo"—modified berries with thick rinds and a fleshy center. While all cucurbits start out with white seeds, watermelons are the only ones with seeds that can then change into various colors.

Despite the childhood myth that swallowing watermelon seeds will cause you to grow a watermelon inside your stomach, all watermelon seeds—mature and immature—are perfectly edible. Some speculate that if you swallow a whole seed it could get stuck in your intestines, but chewing it up a bit will solve that problem. Watermelon seeds are filled with vital nutrients that can give you a large dose of your day's recommended protein intake.

Bonus Explainer: Why do "seedless watermelons" have seeds? They only look like they do. Seedless watermelons are sterile hybrids, but they sometimes contain little hard seed coats. If you look inside of these, you'll find that they're completely empty.