Question about hybrid vegetables
Question about hybrid vegetables
If hybrids produce seeds that aren’t ‘true-to-type’, then how do they keep making the same ones every year?
If you cross AA males with BB females, you get all AB babies ("hybrids").
But if you cross AB males with AB females, you get a mix of AA, AB, AB, and BB babies.
If you want to reliably produce lots of AB babies every year, you need a reserve population of true AA and BB breeding stock.
And that's with just one gene. A specific breed or landrace can have lots of distinct genes.
This! The breeder basically keeps two parental lines that they use to make the seeds. Usually they need to do the crossing pollination by hand somehow and make sure that no foreign pollen fertilize the females. There is a great and accessible book about breeding by Carol Deppe if you're interested in breeding plants in generally https://www.chelseagreen.com/product/breed-your-own-vegetable-varieties/
I've also always been wondering about this and other questions before reading that book.
So when the breeder has a hybrid they like, let’s call that AB (F1), they want to grow and sell more of that variety. So the following year, they will use their reserve population of true AA and BB parents and hand pollinate them. But they still won’t know if the seeds produced will be anything like AB (F1), right? So are those hybrids only available for 1 year or as long as those original seeds remain viable?
True Hybrids (F1) will be identical. But the catch is that you can’t have a “true hybrid f1” if your parent lines are not true breeding. Usually this involves selfing the parental lines 6+ times to obtain purebred (all genes the same allele) lines.
Lots of breeders are loose with that step, so you can occasionally get some variation in your F1. But that’s usually because selfing 2 parents 6+ times, then making the hybrid cross is at least 7 generations. In an annual crop, or even biannual (onion/carrot) this can take 7-14 years.
Seeds of many species, when stored correctly, can still germinate for decades. I have used seed that was 30+ years old several times before.
Breeders produce inbred parental lines by self-pollinating for 5-8 generations (or double-haploid creation).
They then do a small initial seed increase by bulking a generation. Bulking refers to combining the seeds from several plants (I used nethouse with 24 cantaloupe plants and a small young queen honeybee hive inside to produce 0.5-1kg of seed).
This is called basic or breeder seed. This lot is tested for genetic uniformity and seedborne diseases. It's also used for small hybrid seed productions to test out the inbred.
Breeder seed is increased again and bulked to make foundation seed (around 50kg for cantaloupes) This is used to make the first commercial production of the hybrid. It is then increased yet again to produce stock seed (500kg)
Stock seed is what the commercial hybrid is produced from for the rest of its life. Foundation seed is used to produce more stock seed as needed.
The breeder seed and foundation seed are stored carefully to prolong it's life. The stock seed is in the general warehouse with the hybrid seed.
As long as they maintain quality control during the inbred increase process, the resulting hybrid will always be essentially the same.
Now that your question was answered in great detail, you should read or watch something about apple genetics. These trees have a genetic mechanism which ensures that their offspring will never be the same as parents. And thus all commercially grown apple trees across the world are clones. And always were.