Breeding

[Small pumpkin]

I know there's been lots of threads on this but can we go over it again please.
But this time keep it really simple. I really do struggle with getting my head round this

Plant A & plant B produce plant C.
Now what do you do?

How do you reproduce a stable plant C?

sorry I'm being really thick! I'm OK with F1's I think ( plant C in my very technical explanation ).

I start getting completely lost when we get onto F2, F3, F4 and so on.

[nickdub]

I don't think you can tackle the theoretical side of your question without a considerable background understanding of genetics.

You could make practical progress on this subject by narrowing down your question to something like "How do I best select plants A & B to produce a plant C with the characteristics I want ?" this has been the method used by plant (and animal) breeders, together with a lot of repetition and the discarding of unsuccessful crosses. Also since vegetative propagation methods are available cheaply for plants once you have a plant C you like, ie its possible to clone it - hence outcomes like the various varieties of apples.

[Penellype]

I'll try to keep it simple...

There are 2 words that you need to understand first:
Homozygous means that there are identical genes for a particular trait on both strands of DNA, so that the gene will definitely be passed to all offspring.
Dominant means that if the gene is present then the trait will be expressed in favour of another recessive option which may also be present.

Suppose you want a dwarf tomato plant that produces cherry sized plum shaped yellow fruit. You have a dwarf tomato that produces cherry fruit and you have a cordon variety that produces yellow fruit. Its important that the parent plants are homozygous in the traits that you want to develop and that the traits are dominant. (I have no idea if the traits I mention are dominant, but if they weren't dominant and you wanted to definitely have that trait you would need it showing in both parents anyway.)

So, consider the fruit colour (red is likely to be dominant but never mind for this argument). You have a yellow parent, which must be homozygous for the purposes of creating an F1, and a red parent which is homozygous recessive, because if it wasn't it would be yellow (one dominant gene would mask the other recessive one). If you call the yellow dominant gene Y and the red recessive y, then ALL of the offspring must be Yy and because yellow is dominant the fruit will be yellow.

Now consider the dwarf plant, lets call dwarf D. Again you must have homozygous dwarf DD and homozygous recessive dd in the non-dwarf plant. So using exactly the same argument, your F1 offspring are all Dd.

Your cherry fruit plants are CC and the non cherry are cc. F1 offspring are Cc.

Your plum plants are PP and the non-plum are pp. All F1 offsring are Pp.

So, looking at all 4 genes together, you are breeding YYDDCCPP with yyddccpp and your F1s are YyDdCcPp. All of them will produce yellow fruited dwarf cherry plum plants.

The F2, F3 etc simply refer to further generations.

What happens if you breed 2 F1 plants, resulting in the F2 generation? The answer is that you can get any combination of YY, Yy, yy, DD, Dd, dd, CC, Cc, cc and PP, Pp, pp. That's a lot of possible combinations and that's just for 4 genes. Your F2 generation is a muddle of plants with different charactaristics. Breeding the F2 generation may produce some plants that look like the F1s in the F3 generation, but there will be a lot that won't. The only way to guarantee that you get the genes you want (apart from taking cuttings) is to start with parents that are homozygous for those genes because they will always breed true.

This is very simplified - genes may not be completely dominant, the traits I have chosen may not even be controlled by a single gene, and there may be other factors at work that complicate the picture, but the basic explanation is roughly correct.

[Guest]

If you are just after the 'do it' side - you make your cross and save seed. Then select your favourite. then grow as many from those seed to save your favourite again. Keep doing this. Around 8 years it should be stable Voila! Easy peasy

[veggiechicken]

Realseeds have a guide to breeding squashes which is worth reading.

Breed your own squash variety

[Small pumpkin]

If you are just after the 'do it' side - you make your cross and save seed. Then select your favourite. then grow as many from those seed to save your favourite again. Keep doing this. Around 8 years it should be stable Voila! Easy peasy

Now that I understand . Thanks NG

[Scarlet]

Are you thinking of doing a breeding program around that hairy white thing!??!

[veggiechicken]

Is that Bob?

[Small pumpkin]

Are you thinking of doing a breeding program around that hairy white thing!??!

That's exactly what I was thinking. It's weird, I like weird.

Is that Bob?

He11 No

[veggiechicken]

That's exactly what I was thinking. It's weird, I like weird.


He11 No

That's why I thought it was Bob

[Small pumpkin]

That's why I thought it was Bob

A very easy mistake to make. Hairy, white & weird could be Bob , but there's going to be no breeding going on . One Bob is enough

[Mitzi]

F2 and F3 will have the most variation so you should grow as many of those as you can, but only save seed from the ones that have your desirable characteristics.

[Mitzi]

The first thing is to make sure you isolate some of Bob's flowers so you can save some true seed before starting your crossing programme. Just in case the crosses lose the white hairiness.

[rary]

SP, apart from spoiling Bob's night and dashing his hopes, what is it that you hope to do

[Small pumpkin]

SP, apart from spoiling Bob's night and dashing his hopes, what is it that you hope to do

Considering having a go at breeding a chilli.