The Romans had seedless grapes too

And how to grow a tree with no seeds.

Seedless fruits feel like a modern luxury, but the truth is we’ve had seedless fruit varieties for thousands of years. Although it seems like the sort of thing that we would’ve invented recently in a lab to eradicate the most minor of inconveniences from our lives, it turns out that seedless fruits weren’t our idea and have been around forever. Those grapes you see being fed to Julius Ceasar in all those Roman paintings? Seedless, the lot of them.*

*Probably.

But the more you think about seedless fruit, the more questions start to come up. Why don’t they have seeds? How do you plant more trees without a seed? Are they all the product of a lab-coated scientist? Here are the answers.

Seedless fruits are not GMOs

Yes, a common belief is that seedless fruits are genetically-modified organisms (GMOs) but that’s not the case. 

Fruit forms when a flowering plant is pollinated, and is actually the ovary of the plant (which we learned in 3 things that aren’t fruit). It’s the fertilisation of the flower that causes seeds to develop. Sometimes, a natural genetic mutation will result in fruit growing on a plant that hasn’t been fertilised, meaning it doesn’t develop seeds.

Seedless fruit varieties were discovered thousands of years ago and have been selectively bred since for their desirable traits. But that raises another question; how do you breed a plant with no seeds?

Grafting and cuttings

Seedless fruits don’t have seeds (obviously) so growing a seedless fruit tree isn’t as simple as a normal fruit tree. There are two main ways to do it. The first is grafting, which is a whole topic in itself and the science is crazy so I’ll explain it in its own article in a few weeks, but basically grafting is when you create a small wound on one plant and insert the shoot of another plant, resulting in the tissues forming together and creating a hybrid plant that takes characteristics from each of the original two (yes, this actually works). 

The second way is to take a cutting from a branch and plant it into a moist and well-drained soil where it’ll sprout new shoots. Arguably less interesting than squishing two plants together to create a new one, but it works all the same. 

Besides seeds, are there other differences?

Yes, there are other differences between seedless and normal fruits. 

The goal of any plant is to spread seed and reproduce. So, seeds produce a hormone that causes fruit to deteriorate so the seed can be released. This means that seedless fruits often have a longer shelf life. 

There are some debates over the nutritional quality of seeded versus seedless varieties. While seeds can be a good source of fibre and often contain essential oils and minerals, the general consensus seems to be that you don’t need to be picking one over the other for health reasons; fruit should be part of your diet, seedless or not.

One potential downside of seedless fruits is that they’re selectively bred and asexually produced which decreases diversity of the plant population and makes the fruit more vulnerable to disease and pests. This happened with the Gros Michel, which up until the 1950s was the main variety of banana. Because bananas are clonally propagated (produced through asexual reproduction, meaning in the absence of fertilisation) they lack genetic diversity so when Panama disease popped up it swept through the Gros Michel population and essentially wiped it out. Today, you can’t buy a Gros Michel anywhere. They’ve been completely replaced by the Cavendish banana we know today.

There’s nothing unnatural about seedless

That’s the good news! You can enjoy your seedless grapes guilt-free, just like Julius. They’re simply a happy accident produced by nature, which us humans have taken advantage of to get juicy and inconvenience-free fruit. Speaking of minor inconveniences, if you liked this post it really helps if you share it with a few friends. There’s lots more to come over the next few weeks including heirloom varieties (I thought an heirloom was just a type of tomato - it is not) and the insane science of grafting.