Scientists rewrite the origins of the humble watermelon

A classic summertime treat for picnics and barbecues is a nice, cold watermelon. Researchers have published a new study in the "Proceedings of the National Academy of Sciences" that rewrites the origins of the domesticated watermelon we know and love today. The researchers used DNA from greenhouse-grown plants that represent all species and hundreds of varieties of watermelons.The researchers discovered that watermelons most likely came from a wild crop progenitor in Northeast Africa. Scientists on the project say their study corrects a decades-old mistake that lumped watermelons into the same category as the South African citron melon. The new research found that a Sudanese form with non-bitter whitish pulp known as the Kordofan melon is the closest relative to domesticated watermelons.

Interestingly, the new genetic research matches newly interpreted Egyptian tomb paintings suggesting the watermelon may have been consumed in the Nile Valley as a dessert 4000 years ago. Professor Susanne S. Renner says that based on the DNA, the team found watermelons as we know them now with sweet and typically red pulp that can be eaten raw are genetically closest to wild forms native to west Africa and northeast Africa.

Renner says that today's watermelon comes from small genetic stock and is highly susceptible to diseases and insects. Researchers say they have found a variation in three disease resistance genes between the Kordofan melon and the domesticated watermelon. The finding suggests that breeders could potentially use these and other insights from the genome to potentially improve the health and longevity of watermelons.

Renner believes that some of the most important information discovered in the study has to do with the mobility of people and cultural connections to the fruit. Renner says that the Egyptian tomb paintings convinced her that the Egyptians were eating cold watermelon pulp. She says otherwise, why would they placed those huge fruits on flat trays next to grapes and other sweet fruit.