Do plants run out of ‘oomph’?

BenCotto

In 2018 I bought some Petunia Red Velour. These were overwintered and cuttings taken for the 2019. Repeat in 2020, 2021 and this year’s are, so to speak, the great great grandchildren of the originals. I am, though, a little disappointed in them: a bit scraggy, not so bushy and not exactly A1 at Lloyds. 

My my question is whether plants run out of steam. I might be muddling them out somehow with the practice of breeding racehorses, another topic I know sod all about. Or is it simply that the wan state of my petunias is due to eking out an existence in the low light levels of a Midlands winter, living in an unheated greenhouse?

AnniD

Good question @BenCotto .
l've often wondered that when watching Carol Klein taking cuttings and dividing her plants. Surely eventually they've moved so far away from the parent plant that the genetics become diluted, if that makes sense.
I've never propagated anything past the 3rd generation, but they were mostly hardy perennials. 

philippasmith2

I would guess that you can't keep taking cuttings year on year without losing something.  Would it not be the same as attempting to breed anything constantly from the same parents without "adding" some other genetic material ?  You would eventually end up with weaker specimens.  Human families which consistently interbreed over generations without any other input ?
The conditions you grow/rear them in must also be a factor but whether it would fully explain them running out of steam ???
It's an interesting question but not one I am capable of  answering - as you have probably realised @BenCotto
Hopefully someone can offer some insight.

JennyJ

Aren't cuttings and divisions genetically identical to the parents (unless you take a cutting from a "sport" or mutated shoot)?

Obelixx

Yes @JennyJ.   I suspect it varies from plant to plant but, as most nurseries and plant producers rely on cuttings and divisions to propagate perennial plants it can't be that big a deal.

I also remember seeing on GW once a chappy whose passion was dahlias and he said the plants he grew from cutting each year always flowered better than the parent tuber plants so I suspect it may, in this case, be a case of nurture over nature and @BenCotto's manky Birmingham winter.

borgadr

Cuttings are genetic clones of the parent plant, like @JennyJ said. I don't see why they would run out of steam

edhelka

I would guess that some plants/varieties mutate more than others. They can be small, invisible changes, but they can add up over several generations. To better or worse, but usually either worse or closer to whatever the genetic default or basic variety is.

BenCotto

@Obelixx, Birmingham!! I’d accept Leicester or, grudgingly, Peterborough. But Birmingham ... well, I’m shocked! 😉

Obelixx

Sorry @BenCotto.  My poor wee brain which hasn't yet been fed this evening translated Midlands to Birmingham.  Apologies.

Desi_in_London

BenCotto said:

In 2018 I bought some Petunia Red Velour. These were overwintered and cuttings taken for the 2019. Repeat in 2020, 2021 and this year’s are, so to speak, the great great grandchildren of the originals. I am, though, a little disappointed in them....

I think biologically they are identical twins/clones of the originals , so should not be losing vigour , unless somewhere along the way the 'mother plant' from which you took cuttings from had mutated. But I'd be surprised if eg each year your cuttings were sourced from multiple plants that each of those had mutated weaker? So possibly environment vs genes.

JennyJ

Maybe a good excuse to treat yourself to some new ones?