Mericlones and quality?

[Kelo]

What problems can be produced by mericloning an orchid? Are there major differences in flower colour/quality? Can mericloning result in poorer quality plants in general? If so, why would this be?

[lambelkip]

in theory, the clones should be exactly the same as the parent plant, but there will inevitably be mutations in some of the clones. This will have an unpredictable effect on the quality of the plant. The only guarantee is that the mutants will be different in some way.

[Eyebabe]

Mericloning a plant is the quickest way to duplicate the plant genetically other than growing it for a few years and dividing it.
There should NOT be major differences in flower colour and quality. The mericloning process is suppose to make the subsequent plants MORE likely to be identical to the "parent".
Prior to mericloning, if one liked a particular plant you could either grow and divide it, or repeat the cross that created it and begin to grow out seedlings. The divided plant would be genetically identical but the repeated cross not so...well, are we identical to our siblings???

Cloning revolutionized the orchid industry by enabling orchid houses to mass produce a specific plant with an army of identical plants. And this is what the public wanted. Almost every named plant you buy is a mericlone.
A clone can sometimes be worse than the "parent" and sometimes better! Although the mericlone seedlings will be genetically identical, the growing conditions and culture will factor into the quality of the plant and its blooms.
As mericlones are mass produced however, there are always quality issues...and you will have subtle differences among the product. Sometimes even a mutation such as the 'Southern Cross' cultivar of Rlc. George King. This one happened to be desirable.
Some mericlones are made when a seedling from an original cross blooms out really well and looks marketable. More frequently, if a plant is awarded, it is mericloned.
Mericlones can and are awarded as well! Some original seedling cross may get an AM/AOS and be sent for mericloning. One of the mericlones purchased could be grown and shown and receive a higher point AM or an FCC.
Which plant would be "more perfect" then?

So when you buy your next plant, educate yourself.
Is it a seedling from an original cross? (one of many probably and will be individual from it's siblings)
Is it a stem prop, keiki or division from another plant? If so, what is the origin of THAT plant?
Or is it a mericlone?

Many collectors prefer actual divisions of awarded plants especially for breeding purposes. The genetics of course would be more reliable and there is a sense of pride and conservation in having a piece of history growing in your greenhouse. Also, a "first clone" run is something I have become familiar with as well...wondering if subsequent mericlone runs become less reliable as the genetic material is processed again (more diluted?) Thus if a division of awarded is not available a "first clone" would be desirable then.
Someone with more knowledge on this can chime in by all means.
This type of orchid growing has more purpose than just growing a plant to appreciate its bloom and obviously is more costly than buying mericlones.
However, one purpose is no more "worthy" than the other

I have ALL of these types of cenarios in my collection. As a matter of fact, two of my mericlones are blooming almost award quality flowers.
With another year of so of good culture, I may just get a ribbon for one

[Andrew]

Kelo,
It all comes down to (a) how likely a mutation is to occur and (b) how much influence the mutated cell has on the resulting plant. Any time a cell divides there is a chance that the DNA won't be replicated properly and a mutation will occur somewhere in the genome. For the most part mutations do not adversely affect a plant and in most cases there is no noticeable affect of cellular function at all: there is a lot of redundancy built into the genome's influence on the cell and the organism. Problems arise when a mutation in a replicated cell does have a noticeable affect on the cell's function, eg mutations that affect growth, colour, etc which could in turn affect the howthe resulting plant looks and behaves like the original plant.

If we focus on mutations that could make the plant noticeably different than the original plant, during normal plant growth, there is a small chance of a somatic mutation occurring early in the shoot development that could affect the entire new growth. This is how most horticultural sports arise. As the plant grows, the influence of somatic mutations is reduced as there are more and more 'normal' cells and therefore less chance that cells subsequently produced by the mutated cell will find themselves in a part of the new growth plant where the affect of the mutation will be noticed. ie an "alba" mutation that occurs in a growing leaf isn't going to have a noticeable affect. Additionally, as the mutated cells are under some selective pressure from the environment, poorly growing cells will be out competed by the more vigorous normal cells: eg in variegated sports of various plants you need to cut out non-variegated growth to stop the plant reverting back to it's non-variegated form.

In the case of cloned plants not only is the meristematic tissue divided up so that any mutated cell in part of the meristem could go on to form a whole plant comprised solely of mutated cells but the meristem is also treated with hormones to force the cells to multiply under cushy laboratory conditions (ie reduced selective pressure against deleterious mutations) which increases the chance of mutations occurring and mutated cells growing. As such there is a greater (although in reality still pretty small) change that a mericlone will be noticeably different to the original plant.

The chance of getting a noticeably mutated mericlone will increase if smaller sections of meristem are used to produce the mericlones, which increases the chance of a somatic mutation having an effect and if meristem is constantly re-divided to produce new generations of mericlones which increases the chance of cumulative mutation events affecting the mericlone. Reputable cloning labs will take measures to reduce the chance of mutated mericlones - ie producing clones by dividing callus tissue rather than producing cell suspensions by mascerating the callus and by continuously re-deriving meristem from the original plant rather than continuously propagating mericlones from the in vitro cultured meristem generation after generation. Of course where cheap, mass production is needed, good cloning practices often go out the window.

[cday2inflorida]

Andrew and Eyebabe - both of you have taken what is so confusing and explained it both very well.

[Kelo]

Outstanding! Thank you so much for the information. This subject really was explained fabulously. I do have 'Southern Cross' and eagerly await that to blossom. Such a beautiful mistake!

[Eyebabe]

....and you can see that even though you will get "mutations" from the mericloning process; you will still have product that is MORE like the original plant than if you tried to repeat the cross and grow out seedlings!

[Kelo]

Yes, it's something I will leave to others to do. lol

[littlefrog]

A classic example of overcloning is Cycnodes Wine Delight (a clonal name I can't remember right not) FCC/AOS. The original was awesome, as the FCC might suggest, but the color intensity was lost over time as the plant was repeatedly mericloned.

Short of it is that mericlones of mericlones is starting to ask for trouble. There is an innate level of mutation built into the DNA replication machinery. In humans, DNA polymerase makes an error approximately at the rate of one in 100,000 bases. Orchids, being eukaryotes, probably have a similar mutation rate (bacteria are higher). Assuming a genome of approximately 3 billion base pairs, you'd expect ~3000 mutations per cell division.

Most mutations are silent and will never be seen, but it is overly optimistic to believe that mericlones are exactly identical to the original plant. They will be very close, if not indistinguishable, in most cases, but not all. Many interesting differences appear in mericloning, and that has led to many great lines of breeding (harlequin phals are an example if memory serves).

Of course that doesn't even touch the differences in flower (and plant!) based on culture.

[Kelo]

I remember years and years ago some of my fellow UK orchid enthusiasts saying that Vul. Cambria 'Plush' wasn't the plant it used to be because the colour wasn't 'the same'...could that have been due to mericloning the mericlones?