Will seedless watermelons make us superhuman or turn our children into giants? Hardly, but they do give home cooks the power to count chromosomes without a microscope. Just a knife or a hard thunk on the sidewalk are enough to get a watermelon to spill its genetic guts.
If you were reading a Hearst Corporation newspaper in late 1937, you might have thought humanity would eventually be swallowed up by giant carnivorous plants, unwittingly unleashed by uncontrolled biotechnology. The San Francisco Examiner reported on November 21st of that year that the discovery of an “elixir of growth,” meant that “…science may at last have a grip on the steering wheel of evolution, and be able to produce at will almost any kind of species…” including “…a plague of man-eating ones.” In 1937 Americans had much more important things to worry about, just as we do now. Still, that discovery may in fact have threatened one cherished aspect of the American way of life by triggering the slow demise of late summer state fair watermelon seed spitting contests. It doubtlessly paved the way for seedless watermelons, and in 2014 the total harvest of seedless watermelons on American farms – nearly 700 thousand tons – outweighed the seeded watermelon harvest more than 13 to 1 (USDA National Watermelon Report). A similar pattern is emerging this year. Is there no stopping the attack of the seedless watermelons?
And more important, how is it even possible to get seedless fruit from an annual plant? From a plant whose only mode of reproduction is through those very seeds? From a plant that cannot make suckers as bananas do and cannot be perpetuated endlessly through grafts like fruit trees and vines? Such is the challenge posed every single year by watermelons, but thanks to the “elixir of growth” discovered by Albert Blakeslee and subsequent work by Hitoshi Kihara, one of the most prominent agricultural geneticists of the 20th century, the world has an elegant solution. Breeders continually improve the varieties available, and consumer demand keeps growing, yet seedless watermelon production methods have remained essentially unchanged for three quarters of a century. Continue reading