Is F1 alwais better than F2 and a newbie questions

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Shule
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Re: Is F1 alwais better than F2 and a newbie questions

#21

Post: # 45854Unread post Shule
Fri Apr 30, 2021 1:59 am

Barmaley wrote:
Fri Apr 30, 2021 1:46 am
Will it be accurate to say that F8 is a stable plant or we need to go to F20 or something to get it completely stable?
Statistically speaking, it's probably stable, but there's still a chance it might not be completely. You could say the same for an F8000 tomato, but the more generations you grow it, the more likely it is to be stable. Eight to ten generations should be enough.

You can verify stability faster if you grow a whole lot of F3+ plants and find that all of them are the same. However, some different traits might not be obvious in only one set of growing conditions. So, growing out to F8+ is more practical for that kind of stability, if possible, IMO.

You need to make sure cross-pollination doesn't happen in any generation, however.
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Re: Is F1 alwais better than F2 and a newbie questions

#22

Post: # 45883Unread post Doffer
Fri Apr 30, 2021 2:14 pm

Barmaley wrote:
Fri Apr 30, 2021 1:46 am
Will it be accurate to say that F8 is a stable plant or we need to go to F20 or something to get it completely stable?
Maybe this toppic is a answer for youre question:

viewtopic.php?f=19&t=2059&p=42257&hilit ... ics#p42257
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Barmaley
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Re: Is F1 alwais better than F2 and a newbie questions

#23

Post: # 46075Unread post Barmaley
Mon May 03, 2021 10:12 am

Several questions:
1. IS there such thing as a pure tomato which means it they will never get changes in offspring?
2. If I get two stable tomato to cross and will keep doing F1, F2 .....F35 etc will eventually grandchildren become one of the first two stable parents plus a bunch of stable mixes?
3. If I get F1 and will do the same F1, F2, F3 .....F35 etc should I get eventually a stable plant with F1 features?
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Re: Is F1 alwais better than F2 and a newbie questions

#24

Post: # 46110Unread post Shule
Mon May 03, 2021 5:18 pm

@Barmaley

1. Yes, but mutations, sports, selective breeding, epigenetic changes, and horizontal gene transfer can potentially happen. So, even if you have a stable tomato, it can still potentially change without cross-pollination (although noticeable changes shouldn't be terribly common).
2. No. That's a myth. You'll never get one of the true parent varieties back from it's cross-pollinated descendants. You might get something very similar, but it's not the same variety, and something very similar isn't guaranteed to happen. A specific trait, or set of traits, however, might end up being the same (but there's no guarantee, and that's not enough to make it the same breed as the parent).
3. With all of the F1's features? Probably not, but if you have a lot of time and resources, you might be able to manage it. It does happen, but it's not what most breeders do. You can get stable plants pretty easily, but usually they'll have important differences from the F1. If you're going for a stable plant like the F1, this is why it's important to grow lots of plants, and select for the ones that are like the F1 (keep doing that, and the stable version should be like the F1--but it can require a lot of plants, time, and space--and maybe some backcrossing).
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Re: Is F1 alwais better than F2 and a newbie questions

#25

Post: # 46594Unread post Barmaley
Wed May 12, 2021 1:03 am

I understand (it was a big surprise for me to learn it) that the same fruit may be both self pollinated and cross pollinated. This this case if the parent was F1 then F2 grown from its seeds will be different. But in case if it was self-pollinated only - will all F2 tomatoes growing from its seeds identical? If not, if I grow 100 plants will I have 5-6 groups with identical plants or I will get 100 different plants?
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Re: Is F1 alwais better than F2 and a newbie questions

#26

Post: # 46597Unread post Shule
Wed May 12, 2021 1:13 am

Barmaley wrote:
Wed May 12, 2021 1:03 am
I understand (it was a big surprise for me to learn it) that the same fruit may be both self pollinated and cross pollinated. This this case if the parent was F1 then F2 grown from its seeds will be different. But in case if it was self-pollinated only - will all F2 tomatoes growing from its seeds identical? If not, if I grow 100 plants will I have 5-6 groups with identical plants or I will get 100 different plants?
A single unit of pollen corresponds to a single seed. It's common for a fruit to self-pollinate some of its seeds and have some of its other seeds be cross-pollinated by another plant. Sometimes the vast majority will be self-pollinated, and you might have one that is a cross. Tomatoes have perfect flowers (with parts of both sexes in the same flower); so, that's why a single flower can pollinate itself.

The F1 is the first generation since the cross. F2 is the second generation (it's not the result of an additional cross; we're only talking about one cross), etc. If it's an F2 then it definitely came from an F1; you can't get an F2 directly from a true-breeding variety, nor can you get an F2 from seed that was just cross-pollinated. It's in the first generation of the cross (the F1) where you might have some siblings that weren't crossed (or that weren't F1s). So, if you're growing F2s, you know they're F2s, because you saved seeds from an F1 (unless you weren't sure whether it was an F1).

F2s aren't stable and if they really are F2s, they were self-pollinated (if it's crossed again, you generally call that an F1 hybrid, again; it's not the same F1 hybrid, however). So, each and every F2 seed (each and every child of an F1) will be genetically different.

The reason commercial F1 hybrids seem to be reliable in the traits that they express in the F1 generation is because both parents have only homozygous traits, and when they cross, you get the same combination every time you make that same cross between those same two varieties. But, the F2s (which are the offspring of the F1) will be an unpredictable mix if they were self-pollinated, and if they were cross-pollinated, then they're not F2s, and they're still unpredictable (because the mother plant wasn't stable).
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