What Are the White Seeds in a Seedless Watermelon?

History

• Seedless watermelons have been produced for about 50 years and have become far more popular in the marketplace than seeded watermelons. In 1949, researcher Warren Barham began experimenting with breeding watermelons for smaller seeds. He discovered that certain "parent" watermelons, when crossed, produced seed that resulted in seedless watermelons.

Method

• A seeded watermelon contains 22 chromosomes (diploid). When a chemical called colchicine is applied, the chromosomes double to 44 (tetraploid). Pollinating a 44-chromosome plant's flower with the pollen from a 22-chromosome plant results in a 33-chromosome plant (triploid). To produce fruit, the sterile triploid plant needs to be pollinated by a normal, seeded watermelon plant. But the fruit will be seedless.

Growing

• At first, to grow a crop of seedless watermelons, farmers needed to plant seeded watermelons nearby for pollination. Now, however, non-fruiting hybrids of watermelon plants have been developed. They produce flowers for cross-pollination by bees or by hand, but they produce no watermelons. Because seedless watermelons don't put any energy into seed production, their flesh is often sweeter and their vines more vigorous.

Popularity

• Like seedless grapes, seedless watermelons have become favorites at the grocery store. In 2004, according to the National Watermelon Promotion Board, only 16 percent of watermelons sold in grocery stores had seeds. Seedless watermelons are firmer and keep longer because the flesh is more solid than the flesh of seeded varieties.