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-   -   Generational ID for mericlones? (https://www.orchidboard.com/community/scientific-matters/102785-generational-id-mericlones.html)

Fairorchids 03-11-2020 07:20 AM

Generational ID for mericlones?
 
When dealing with seed grown plants, we identify generations with F1, F2, etc. Example:

Paph Hellas 'Westonbirt' is an F1 (original plant, first generation seed grown).

Paph Hellas 'Sunset' is an F2 (from selfing of 'Westonbirt').

If we selfed 'Sunset' (or crossed it with 'Westonbirt'), we would produce F3.

I have seen the 'F' designations used for meristems in the Cattleya group, but wonder whether that is a correct use?

This propagation method is different. It would be nice if we could identify whether a given plant is a meristem made from the original plant, or from a meristem from a meristem (perhaps 2 or 3 times over).

isurus79 03-18-2020 01:04 PM

That sure would be nice! I've never heard of such a label though.

Fairorchids 03-20-2020 08:13 AM

For Catt meristems, F1 is supposed to designate that the plant was produced from a mother division.
I have never seen anyone admitting to their meristems being 2, 3 or 4 times removed from a mother division.

katsucats 06-08-2021 01:27 AM

I'm not an expert so I could be wrong, but my understanding is that F1 refers to the first filial generation between two distinct lines. Then, F2 refers to sibling crosses between an F1 line. And F3 refers to the sibling crosses between 2 F2's.

I'm not sure if I've seen anyone refer to a selfing or backcross as F2. That feels incorrect. And a meristem should be an exact replica of the mother plant, so it should not be referred to as F1, in my opinion.

But maybe there's different terminology in the orchid industry, I don't know.

camille1585 06-08-2021 02:01 AM

Quote:

Originally Posted by katsucats (Post 959637)
I'm not an expert so I could be wrong, but my understanding is that F1 refers to the first filial generation between two distinct lines. Then, F2 refers to sibling crosses between an F1 line. And F3 refers to the sibling crosses between 2 F2's.

I'm not sure if I've seen anyone refer to a selfing or backcross as F2. That feels incorrect. And a meristem should be an exact replica of the mother plant, so it should not be referred to as F1, in my opinion.

But maybe there's different terminology in the orchid industry, I don't know.

F1 must result from a cross between 2 parental lines, but F2 (and subsequent generations) can be obtained by either crossing 2 F1 plants, or selfing a F1 plant. The process is the same in that no new genetic material is being introduced. Backcrossing to one of the original parents would generally be named BC1 instead of F2 (this is in the crop breeding world at least). To push things even further, in crop breeding (I'm talking cereals and vegetables) an F1 refers specifically to crossing 2 homozygous parental lines, leading to nearly genetically identical F1 offspring.

And I agree that it seems incorrect to refer to meristems as F1/2/3, since these are 'copies' of a plant, and not reshuffling of DNA through crosses of any sort.

katsucats 06-08-2021 07:19 AM

In the cannabis industry, I've seen selfings referred to as S1, S2, etc. I'm not sure if that's because cannabis plants are either male, female, or intersexed, so selfings only produce intersexed plants. But this doesn't afflict other crops. Anyways, thanks for clarifying.

Ray 06-08-2021 08:42 AM

Why not create one? M1 for a mericlone made from a seed grown plant, M2 for the clones made from an M1, etc.

Unfortunately, it raises other issues.

“Clone”, “mericlone”, and “meristem” get casually used fairly interchangeably. So I guess the “M” designation would be limited to in vitro propagation, which makes me wonder how we deal with divisions?

Fairorchids 06-08-2021 09:16 AM

A plant grown from a division of a seed grown plant is considered a 'Mother Division' (as compared to a meristem/clone). It remains a genetically identical plant to the original plant.

A plant grown from a division of a meristem/clone remains a meristem/clone. And currently we don't know, whether it was produced from a mother division, or perhaps 4-6 meristem processes removed. If it is produced from a mother division, it is most likely genetically identical; if it is 4-6 processes removed, there could be mutations, so it is not necessarily genetically identical.

As an example, I had Rth. Psycho Bride 'NN' shipped from Hawaii in 2014. That plant had yellow flowers.

I lost that plant in the Dec 2017 freeze, so I went looking for a replacement. I found a plant supplied by the same nursery in 2018. This younger meristem (several processes removed) has pink flowers!

voyager 08-29-2021 09:34 PM

F1, F2, and so on, are designations for genetic crosses.
F1 is a first generation cross.
It is a combination of the genes from the 2 parents, plants in the case of orchids.

F1s have 1/2 of the genetic code from each parents.
They are probably unstable crosses.
The genetics and characteristics can be different in separate individuals.

F2s are F1s crossed with each other.
Again, usually to enhance genetic characteristics.
If crossed carefully, by F3 they can begin to stabilize into a genetically repeatable breed.
Sometimes F4 or more is needed to get stability.

Using F1 for mericlones is part of the "do-as-you-want" that runs amok with orchid "experts".

Fairorchids 08-30-2021 07:10 AM

I agree.

However, as a consumer it would be nice to know whether the meristem you are contemplating buying is made from the original plant, or another meristem six steps removed.


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