Life's Great Mysteries - How can farmers grow seedless watermelons if seedless watermelons don’t have seeds?

Let’s say you buy a watermelon at the store, and it tastes so good that you want to extract the seeds and grow your own wonderful watermelons. But it’s a seedless watermelon, so you’re out of luck. Hmm… then how did the watermelon come into existence in the first place?

Well, first of all, seedless watermelons actually do have seeds. You’ve seen them, those wimpy little white seed wannabes in the watermelon's flesh. You can just eat those seed wannabes without any problems because they do not have the hard black exterior shell that regular watermelon seeds have.

In the flower stage in normal watermelons (with seeds), an egg cell in a female flower gets fertilized by pollen from a male flower, then the fertilized egg grows a fruit. Inside that developing fruit, the seeds are properly fertilized, which causes them to grow that hard shell (called the testa). But in seedless watermelons, the eggs are not properly fertilized. But why not?

As with most sexually producing life forms, the egg contains one set of chromosomes and the pollen (or sperm) contains one set of chromosomes. After fertilization, the fertilized egg then has two sets of chromosomes. That’s the way things normally work.

However, when growing seedless watermelons, the farmer treats the young watermelon plants with a chemical called colchicine, which causes the eggs in the flowers to develop two sets of chromosomes instead of only one. When those eggs get pollinated, they then have three sets of chromosomes. These can grow into big watermelon fruits, but the seeds in those particular watermelons are not genetically viable—they cannot get properly fertilized and therefore do not grow the hard, black testa. Those fruits are marketed as “seedless” watermelons.

So, farmers still must plant regular watermelon seeds, then they treat the young plants with colchicine, and those plants grow "seedless" watermelons.

I am of the opinion that food tastes better if you understand how it came to be. So, maybe your next slice of seedless watermelon will taste better than ever! Or, you could just stick with seeded watermelons because the seeds are fun to spit.

Photo Credit:
- Seedless watermelon - DepositPhotos