Watermelon is the fruit of a vining plant originally found in southern Africa. This wild African watermelon has white flesh and is largely inedible due to its bitterness.
Recently, DNA has been isolated and sequenced from a watermelon leaf discovered in a 3,500-year-old Egyptian tomb. It had the genotype of the African watermelon, but two of the melon's genes were modified causing it to develop a fruit with red flesh and a sweet taste. This confirms that Egyptian tomb paintings showing watermelons indicates that they were probably cultivating them several thousand years ago, and that the melons were similar to the ones we enjoy today.
A watermelon is 92 percent water and is cousin to cucumbers, pumpkins and squash. A watermelon's stripes are an indicator of variety, but with more than 1,200 varieties grown in 96 countries worldwide, there are many variations. Some watermelon varieties don't even have stripes.
By weight, watermelon is the most consumed melon in the U.S., followed by cantaloupe and honeydew. The U.S. currently ranks sixth in the worldwide production of this popular fruit.
According to the Guinness Book of Records, the world's heaviest watermelon was grown in Tennessee and weighed 350.5 pounds.
Seedless watermelons were produced more than 50 years ago. These melons lack the firm black seeds that are mature and can grow into a new watermelon vine which can produce fruit. They may still possess small, sterile white seeds that are not able to produce a new melon vine. However, these seeds are soft and perfectly safe to swallow while eating.
A seedless watermelon is the product of genetic modification resulting from simple cross breeding. A diploid plant — bearing the standard two sets of chromosomes — is crossed with a tetraploid plant — having four sets of chromosomes. This results in a fruit that has seeds with three sets of chromosomes (triploid). These triploid seeds remain very small and immature and are incapable of sprouting to produce a new plant.