Meristems not all the same?
 

I was looking at some orchid sources and came upon this statement, which puzzled me.

It indicates that not all mericlones are true-to-form, and that there is recognizable variation.

If this is the case,how does one tell if a mericlone is a true representation of the original?

quote-

"Blc. Goldenzelle
(C. Horace 'Maxima' AM/AOS x Blc. Fortune 'Golden Throne' HCC/AOS). One of the finest hybrids of the past ten years. Sturdy, extremely vigorous, fast growing plants with tight growth systems that often produce multiple leads. Full, beautiful flowers. Plants selected for this offering are some of the finest from the grex and are mature flowered varieties.
‘Lemon Chiffon' AM/AOS. Form ORC-LAB. $350.00. Form YWR. $100.00
Note: These are mericlones obtained from Stewart Orchids and are vigorous, heavy bulbed and leaved unlike many of the mericlones on the market. Full butter-yellow with red-purple dart in center of broad lip. Plants normally develop multiple leads. The ORC-LAB form is quite flat and yellow flowers are up to 6”. The center lines of the petals are slightly lighter yellow. The YWR form are slightly smaller, more yellow and more ruffled. All sizable plants with substantial bulbs. "

Mericlones exhibit differences just as human identical (homozygous) twins exhibit differences.

Every time a cell divides there is a small chance that a mutation will occur, and one new cell is no longer genetically identical to the ones before. That is equally likely to happen in the meristem of an orchid plant, or in meristem tissue in a cloning flask. But there is a big difference in what happens next.

One cell in the meristem of a plant usually goes on to become part of a leaf or stem. Only if it happens to win the lottery and give rise to a full new growth, and then goes on to flower, do we have any chance of seeing it.

But one cell in a cloning flask has just as much chance as any other cell to go on and become a whole new plant, and hundreds or thousands of them will. So we see the changes in the flower that never would have been visible in a few cells inside a stem or leaf. Mutations happen. That is literally a fact of life.

They are making a serious mistake in your example though. If a plant is clearly not identical to the original, it should not get the name 'Lemon Chiffon' at all. That is reserved for plants that are genetically identical to the original. They should be given new names that have no chance of being confused with the original. It is fine to market it as a mutation found among clones of 'Lemon Chiffon' but Form this and Form that are just another step down the road to all orchid names being meaningless.

According to a local Cattleya afficionado, who usually buys mother divisions only, when you meristem a Cattleya on average you will get:

60% or so generally identical to the mother plant for that meristem process (see below).
20% better
20% worse

The number of deviations supposedly increase the more times you cut up the cell cluster (= the greater the number of meristems you produce).

Also, meristems of the mother plant are more likely to be true, than a meristem produced from another meristem. As growers who do not have a piece of the mother plant will have to start with a meristem, their subsequent meristems are more likely to show deviations.

When the deviation is recognizable, it is considered a sport, which can then be given a new clonal name. If the deviation is minor, it usually maintains the original clonal name. However, this gives rise to both better and inferior versions of that clone.

Example: Waldor Orchids purchased a number of meristems of Cattleya Caudebec 'Carmela'. About 10% turned out to be spontaneous 4N mutations, which are significantly larger, but carry fewer flowers on the spike (max 10-11, vs 15+ on 'Carmela'). They selected the best one, which is recognized as Cattleya Caudebec 'Linwood' AM/AOS, and in turn meristem propagated that plant.

The 2 key points here influencing sport development are the number of mericlones allowed and the importance of using tissue from the mother plant. The more cells divided or the use of a mericlone for tissue, the greater the chance of mutation or sport. :twocents:

I interpret that quoted text in the original post a bit differently from some of the others that have replied.

Blc. Goldenzelle is the grex (you can get a lot of variation within a grex). My understanding is that any C. Horace x Blc. Fortune is still considered the grex Blc. Goldenzelle.

I thought the quoted text implied that ‘Lemon Chiffon' AM/AOS (clonal name & award) was a particularly vigorous specimen produced from the grex. Therefore mericlones of ‘Lemon Chiffon' AM/AOS are different (better in the opinion of the writer of that listing) compared to other mericlones that might come from other plants of the same grex.

Again, just my interpretation.

On rereading the original post, I think you are absolutely correct in your reply. Although the general comments on mericlones are still correct, they are not the answers to Plant Buddy's question. Thank you for getting us back on track. :bowing

You are right. Opening question refers to two different forms of 'Lemon Chiffon', one referenced ORC-LAB and another referenced YWR.

This is a gray area. You could argue that neither is a true 'LC'; but if they are very close and difference is primarily in plant vigor or size, you could make a strong argument for retaining the clonal name.

This is why some people are willing to pay a premium to obtain a mother division.

If there is a significant variation of the mericlone, many will attach another name and not call it the same as the tissue meristemmed. This is especially true for the stable pelorics coming from a non-peloric form. For example: Cym. Strathdon 'Cooksbridge' mutated to a stable petal peloric which was given the cultivar name of 'Cooksbridge Fantasy' and has been awarded under that name.