Jimmy Doherty in Darwin's Garden

[Digger Don]

Thursday evening showed Jimmy Doherty experimenting with plants, demonstrating that plants which were self pollinated had offspring which were half as strong as those externally pollinated. Presumably their offspring would be proportionately weaker still and so on; Darwin, Survival, etc. etc.
How does this tie in with tomatoes, which usually are self pollinating, and yet Gardeners Delight e.g. have been giving excellent results for 40 years, to my personal knowledge?
Any botanists out there ?

[kirsty b]

Not a botanist, but wanted to comment on what a fascinating programme it is. Have watched both episodes so far and its been great. My daughter loves it too.

[Hilary B]

How many people grow tomatoes from self-pollinated seed?

Of course there was a fair amount of over-simplification as well. in-breeding is how 'breeds' have been created in domestic animals. If there is suitable culling of the failures, it can actually be advantageous, until things change.....
Interesting that there was no mention of primroses as an example of a flower that 'goes to some trouble' to minimise the risk of self-pollination. The flowers come in 2 'types' with different sizes of pollen grains, different shaped 'receptor' areas for the pollen to land on, and a basic design that facilitates pollination by the 'other sort' because one has the anthers high and the pistil low, so the bee gets pollen in her head, and transfers it when visiting the 'other type' which has a high pistil and low anthers, and where the bee picks up pollen to transfer to the first type......

[Digger Don]

Jimmy Doherty in Darwin's Garden

[QUOTE=Hilary B;401497]How many people grow tomatoes from self-pollinated seed?

Don't Quite understand your point Hilary. Anyone ( me e.g.) who saves seed from their own toms automatically has a high probability of it being from self pollinated flowers.
Don't know what the commercial people do, except on F1 seeds.

Don

[Hilary B]

[QUOTE=Digger Don;401739]

How many people grow tomatoes from self-pollinated seed?

Don't Quite understand your point Hilary. Anyone ( me e.g.) who saves seed from their own toms automatically has a high probability of it being from self pollinated flowers.
Don't know what the commercial people do, except on F1 seeds.

Don

I doubt commercial ones are self pollinated (I know about F1). Unless you exclude pollinating insects, or induce self-pollination by 'paintbrush' or similar method, your seed will probably be from pollination within the group of plants, but that isn't self-pollination, just in-breeding on a lesser scale.

[Eyren]

There's a great thread on the vine somewhere that explains the difference between inbreeding and outbreeding plants. In summary, some plants can inbreed indefinitely without genetic penalty, and you can save their seed because the flowers pollinate themselves before they open. Peas, French beans and tomatoes fall into this group, IIRC. That may be why Gregor Mendel worked with peas - they don't cross easily, so he was able to control their breeding by artificial fertilization.

Other plants have to outbreed, like animals, or they suffer genetic defects. They rely on wind or insects to carry pollen around, and it means that they don't breed true so seed-saving is less reliable. Broad beans, runner beans and brassicas fall into this group.

That said, I have been enjoying the series so far!

[Digger Don]

Thanks Eyren , solves my conundrum, and keeps me happy with my Gardeners Delight.
Don