Melon enthusiasts have spent decades tracing the origins of the common watermelon, a popular fruit that has impacted cultures across the globe for thousands of years. And now, DNA testing has revealed its oldest ancestor, the Sudanese Kordofan melon.
Before Susanne S. Renner and her team of researchers began sequencing the DNA of undomesticated plants in the watermelon’s genus (Citrullus), most botanists agreed that the watermelon’s origins lay in the South African citron melon. This hypothesis, first introduced by a student of taxonomist Carl Linneaus who visited Cape Town 150 years ago, was incorrect.
DNA testing showed that the South African citron melon is very different from the common watermelon that we find in grocery stores today. Instead, the closest wild relative appears to be the Sudanese Kordofan melon, a fruit with a white pulp. Its insides may not look appetizing, but the Kordofan isn’t too bitter and can be eaten raw, making it the perfect candidate for domestication. (Watermelons with white pulp were common until recently. You can still buy heirloom watermelons with white pulp!)
Studying the origins of watermelons may seem like a useless task, but doing so could help defend the watermelon from extinction. Modern farming methods have severely limited the gene pool of watermelons (and other edible plants), which means that nearly all watermelons have the same genetic vulnerabilities to disease, pests, and fungus. The Kordofan melon could help us diversify the watermelon gene pool, or at the very least, help us figure out what genetic protections the watermelon lost through domestication.
Source: PNAS via Smithsonian