We have seedless grapes, oranges, and watermellon… but is that the limit to our “seedless technology”? Around Halloween, some seedless pumpkins would be awfully handy.
In: Biology
Seedless plants can’t produce *the actual seeds* due to basically having too many copies of DNA, which doesn’t allow the normal process where each parent passing along exactly 1/2 of the DNA needed for the next generation.
As you can notice with seedless watermelons, the plants may still try to produce seeds, but they’re not fully formed. The plant still forms the rest of the fruit which is important, because that’s of course what we eat. This means the inner stringy *stuff* in pumpkins, which contains seeds, would likely still exist even without seeds inside it, and it wouldn’t be any easier to clean the pumpkin for carving.
Seedless plants are also harder to reproduce because you can’t plant the seeds. You either need to take a cutting to grow basically a copy of the plant starting with a branch (instead of starting with a seed) or you need to go through the process to create seeds that produce a seedless plant to begin with, which is tricky.
You wouldn’t want to apply this to pumpkins because their vines die every year. So you’d need to re-make a seedless pumpkin variety every year. Much easier/cheaper to take seeds from this year’s pumpkins and plant them to grow next year’s pumpkins.
Most of our seedless fruit grows on vines or trees that can be planted once and produce for many years.
There are lots of different ways of producing seedless fruits, but as far as I’m aware they all involve some kind of genetic abnormality that prevents either the growth or hardening of seeds.
Seedless pumpkins are possible. A brief google search suggests they have even been created before. The reason they haven’t caught on will be one of profit – it’s simply not profitable to spend time and effort creating seedless pumpkins, as it’s a once per year crop, and most people are willing to just scoop out the seeds themselves, as it’s not actually very difficult. Some people also enjoy consuming the seeds.
There are a lot of ideas that are theoretically possible, and many that are even produced on the very small scale, but that never make it big because they’re not viable businesses.
Fruits become seedless in a couple different ways.
Some plants grow their fruits even if they’re not fertilized and simply omit the seeds. These are easy to make seedless, just cover the flowers so they don’t get pollinated. We do this with pineapples.
Other seedless fruits are hybrids – crosses between two plants with different numbers of chromosomes that disrupt the seed production. You have to cross-breed new hybrids every time since the plants are infertile. Seedless watermelons use this process.
Then there’s the mutants – plants with a genetic defect that halts seed production entirely. These plants are completely sterile and cannot be re-bred, so every single one is a clone. Every banana you’ve ever eaten is a genetic clone from just one or two mutant plants that have been turned into an entire plantation through cutting and grafting. Many seedless grapes fall into this group too.
If a plant doesn’t cross-breed, doesn’t fruit without pollination, and doesn’t have any known seedless mutations, it’s unlikely to have a seedless variation available.
Why would you want a seedless pumpkin? Haven’t you ever baked pumpkin seeds? They’re awesome to snack on.
Fun fact: the bananas that we eat are seedless. The natural banana has seeds and the bananas we eat are the product of a mutation where the DNA is triploid (3 of each chromosome, rather than a pair of each chromosome). They are reproduced via cutting off pieces and planting them because they can’t reproduce naturally. Since we’ve never eaten nor seen bananas with seeds, we aren’t aware that there ever were seeds in them. But we’ve all seen grapes, oranges, and watermelons with seeds so we realize that the seedless types are anomalous for those fruits.
I believe all of the seedless varieties were the product of random mutations that alert farmers took advantage of. If a seedless pumpkin came along, someone would probably do something about it. But part of the fun of carving pumpkins is scooping out seeds. Perhaps seedless pumpkins wouldn’t have the same shape? And some people like roasting and eating pumpkin seeds.
Plants generally need seeds to make more plants. If you somehow manage to create a version without seeds, the genetic line stops there.
So our two strategies for creating seedless plants are either to carefully tend existing seedless plants (like grapes and oranges, where parts can be cut and grafted into new environments), or trick plants with seeds into sometimes producing seedless offspring (like watermelon, where cross-breeding two different varieties generates seedless offspring). We’ve figured out how to do this for only a small set of plants and may never discover techniques for some.
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