A comprehensive introduction to how seedless watermelons are grown and the key techniques for planting seedless watermelons, please feel free to correct any mistakes!
In the hot summer, is there anything more delightful than eating a few slices of cold, sweet, and juicy watermelon?
Of course, there is! That would be eating a few slices of cold, sweet, and juicy seedless watermelon.
Seedless watermelon
This is one of the reasons why seedless watermelons are among the greatest inventions of all time. But there is a contradiction, much like the famous "which came first, the chicken or the egg?" question. It is well known that watermelons reproduce through seeds, and many friends may have had the experience of accidentally or intentionally throwing watermelon seeds into a flowerpot or yard, only to find watermelon seedlings or even small watermelons growing afterward. So the question arises, how do seedless watermelons come into existence without seeds?
It requires substances that can alter the genome of the watermelon and simultaneously plant three different genetically distinct watermelon plants. This method can also produce various seedless fruits, which sounds magical, doesn't it?
About 5000 years ago, the wild ancestors of watermelons grew in Africa, producing small, bitter, and hard fruits. After several centuries of selection and breeding, watermelons slowly evolved into the sweet, large, and juicy red fruits we enjoy today, complete with black, glossy seeds.
Then, about 80 years ago, Japanese scientists directly created seedless watermelon varieties by modifying the genome of the watermelon. They used a process called "mutation breeding": exposing the plants to certain environments (such as strong radiation) to induce changes in their genomes, then selecting the offspring with the desired qualities.
In 1939, scientists used a chemical called colchicine, which, when applied to plant cells, prevents them from properly separating the double DNA produced by cell division, leading to doubled DNA in the cells. Typically, animals, including humans, cannot survive with an abnormal number of chromosomes (i.e., DNA), but plants seem to be unaffected by this. A professor at Kyoto University used colchicine to make the normally diploid watermelon plants produce tetraploid watermelons. Then, he had the brilliant idea of crossbreeding diploid and tetraploid watermelons to obtain seeds with triple DNA. However, planting this genetic monster is not the final step in producing seedless watermelons, as they cannot bear fruit normally after flowering. Therefore, to obtain seedless watermelons, artificial pollination must be performed, which involves using the mature pollen from ordinary diploid watermelons to stimulate the ovary development of the triploid watermelons into fruit. The resulting watermelons are seedless.
Does this sound complicated? Moreover, since triploid watermelons do not have seeds, they cannot be used to continue producing seedless watermelons. This means that to continuously produce seedless watermelons, it is necessary to maintain the planting of both diploid and tetraploid watermelons and use them for breeding during the繁殖 period. This requires planting three different varieties of watermelons simultaneously and considerable human intervention. While it sounds like a lot of work, people love seedless watermelons, and with a market for them, the effort is worth it for farmers.
How seedless watermelons are grown
Seedless watermelon production process diagram
Now, researchers have tried various methods to make the treatment process more efficient, for instance, they have developed diploid plants that do not produce female flowers, so farmers can plant them to obtain pollen without worrying about accidentally producing any seeded watermelons.
Today, watermelons are not the only seedless fruit. Through similar DNA doubling operations, we have produced seedless grapes, seedless oranges, seedless bananas, and more. This seems counterintuitive, as we never think of any of them as genetically modified organisms, even though they have indeed undergone genetic modification. Only crops like modern genetically modified soybeans are referred to as "genetically modified."
The detailed explanation above about how seedless watermelons are grown and the key techniques for planting seedless watermelons is hoped to provide you with assistance in green plant management!