Grex vs. Cultivar

[Shoreguy]

I am totally confused by these terms.

What do they really mean and what is the difference?

For each of the following, which applies?

Neof. Tamakongo

Neof. Bulihwan

Neof. Manjushage

Neof. Mangekyo

Neof. Beniougi

[Hakumin]

Originally Posted by Shoreguy

What do they really mean and what is the difference?

A grex is a name given to an orchid hybrid as defined by its parentage. It is a name given only to hybrids and as such, a pure species does not have a grex. However, Grexes are pretty much only used in western style orchid horticulture (e.g. RHS, AOS) and its offshoots (e.g. JOGA, TOGA, etc). Outside of the orchid world, a different naming system is used.

So, for example, Neostylis Lou Sneary is a Grex. This is because it is the name given to the cross between Neofinetia falcata and Rhyncostylis coelestis regardless of its visible characteristics.

However, there is also a Neostylis Lou Sneary 'Bluebird'. In this case 'Bluebird' is a cultivar of the Lou Sneary grex.

Cultivar is a portmanteau of the words Cultivated Variety. This is a bit more complicated due to different horticultural circles using the term cultivar a bit differently. However the use of term cultivar, using one definition or another, is pretty much universal in the horticultural world as a whole.

The AOS basically states that the cultivar of an orchid is defined by its genes, so that only genetically identical plants (i.e. divisions and mericlones) can share a cultivar name.

However, the Neo world uses the word cultivar in a different manner, basically following the definitions provided by the International Code for Nomenclature of Cultivated Plants.

There, it states:

2.3. A cultivar is an assemblage of plants that (a) has been selected for a particular character or combination of characters, (b) is distinct, uniform, and stable in these characters, and (c) when propagated by appropriate means, retains those characters....

2.4. Cultivars differ in their mode of origin and reproduction, for example as described in Art. 2.5-2.19. Whatever the means of propagation, only those plants which maintain the characters that define a particular cultivar may be included within that cultivar.

...

2.20. In considering whether two or more plants belong to the same or different cultivars, their origins are irrelevant. Cultivars that cannot be distinguished from others by any of the means currently adopted for cultivar determination in the group concerned are treated as one cultivar.

In articles 2.5-2.19, it explains the various different means that a cultivar may be propagated, including division, cloning, seed propagation, hybridization, line-breeding, grafting, etc. Basically as long as the plants comprising the cultivar retain the same set of defining characteristics, no matter how wide or narrow that set of characteristics is, it can be considered part of the cultivar regardless of how it was propagated.

This definition does happen to fly in the face of what many western orchid growers believe, because the AOS requires that an orchid cultivar that they register be strictly bound by its genetic identity. However, in reality, it fits together just fine because genotype in the end is simply the defining characteristic used by the AOS to define the cultivars that they register. Incidentally, the RHS explicitly concedes that the naming of grexes and cultivars are governed by the ICNCP, although the RHS itself does not register cultivars of orchids, only Grexes.

(On a side note, Neos on the other hand could never really be adapted to fit into the AOS' definition of cultivar partly because of the complexities involved with chimerism present in many neo varieties. For example, 'Oemaru-shima', 'Daidomaru' and 'Mikado' are all technically genetically identical, but due to chimerism and meristem structure, they each have different stable phenotypes.)

I apologize for the long spiel, but I'm trying to be specific here and showing references because I've come across way too many orchid growers who are hard headedly adamant that the AOS definition is the only correct definition, and that it applies to all plants.

Originally Posted by Shoreguy

For each of the following, which applies?

Neof. Tamakongo

Neof. Bulihwan

Neof. Manjushage

Neof. Mangekyo

Neof. Beniougi

All of these are cultivar names. Pure neos being a pure species do not have a Grex.

Of the neo hybrids that are commonly traded in Japan, they would have a Grex only if the parentage is known. Unfortunately, due to the lack of importance historically placed on Neo hybrid parentage, most of them are now unknown. Because of this, the names that they come with are usually cultivar names. Some examples of these hybrid cultivars include 'Ogonmaru', 'Kibana-Manjushage', 'Myeongwol', 'Choukou' etc.

[Shoreguy]

Thank you Hakumin.

For me, only the last paragraph and preceding sentence can sink in at this time. All the previous material will require multiple readings and hopefully at least some of it will be absorbed.

I feared the reply was going to be involved but not this involved.

[Ray]

Can I try to simplify it?

“Grex”= hybrid involving 2 different species or hybrids, or one of each. Not a species.

“Cultivar” = a plant having unique traits, but that does not demonstrate those traits in sexually produced offspring - i.e., does not “breed true”. If it did, it is considered a true variety..

[Hakumin]

Originally Posted by Ray

“Cultivar” = a plant having unique traits, but that does not demonstrate those traits in sexually produced offspring - i.e., does not “breed true”. If it did, it is considered a true variety..

Having traits that are inherited by sexually produced offspring are absolutely accepted for a cultivar. It does not matter how the traits are retained or transmitted to the individuals that comprise a cultivar.

All that matters is that those traits are stable in each individual, and those traits can be transmitted when propagated using any appropriate means, including sexual reproduction.

It says in the code:

2.12. An assemblage of individual plants grown from seed derived from
uncontrolled pollination may form a cultivar when it meets the criteria laid down in
Art. 2.3 and when it can be distinguished consistently by one or more characters even
though the individual plants of the assemblage may not necessarily be genetically
uniform.

2.13. An assemblage of plants grown from seed collected from a particular
provenance on more than one occasion and clearly distinguishable by one or more
characters (a topovariant) may form a cultivar.

2.14. Plants of a line (which results from repeated self-fertilization or inbreeding)
may form a cultivar.

2.15. Plants of a multiline (which is made up from several closely related lines)
may form a cultivar.

2.16. Plants of the same F1 hybrid (the result of a deliberate repeatable single cross
between two pure-bred lines) may form a cultivar.

[Ray]

Thanks for the clarification.

[Shoreguy]

Originally Posted by Ray

Thanks for the clarification.

Ray,

Thanks for your first post, I am still trying to wend my way thru all of this and may give myself a break. This hobby is supposed to be fun and not a chore. At my age, I have enough problems, not to mention the major issue we all are facing.

[Hakumin]

Here's a tl;dr.

1. Grex = A name given to an interspecies orchid hybrid, defined only by the parentage.
   
2. Cultivar (overall) = A name given to a group of plants within the same plant species or hybrid that all share a defining set of characteristics, that can be propagated using one or more of any method including division, cloning, sexual reproduction, grafting, genetic engineering, etc.
   
3. Cultivar (orchids only, as recognized by the AOS) = A group of genetically identical orchids that has been recognized by the AOS usually after one of them being awarded.

Japanese and Korean Neo cultivars, although they are orchids, follow #2.

[Shoreguy]

Originally Posted by Hakumin

Here's a tl:dr.

1. Grex = A name given to an interspecies orchid hybrid, defined only by the parentage.
   
2. Cultivar (overall) = A name given to a group of plants within the same plant species or hybrid that all share a defining set of characteristics that can be propagated using any means including division, cloning, and sexual reproduction.
   
3. Cultivar (orchids only as registered by the AOS) = A group of genetically identical orchids that has been registered by the AOS.

Japanese and Korean Neo cultivars, although they are orchids, follow #2.

Hakumin,

For clarification, can I assume that to qualify for #2, a plant need only to propagate by at least one but not necessarily all methods? I believe Neof. Gojofukurin (and many others) would be an example which I thought does not propagate sexually and possibly not by mericloning either although I could be wrong on that.

[Hakumin]

Originally Posted by Shoreguy

For clarification, can I assume that to qualify for #2, a plant need only to propagate by at least one but not necessarily all methods?

Yes, exactly.

Originally Posted by Shoreguy

I believe Neof. Gojofukurin (and many others) would be an example which I thought does not propagate sexually and possibly not by mericloning either although I could be wrong on that.

Because of how chimerism works in plants, yes, proper fukurin varieties, including Gojofukurin, cannot be propagated sexually or by mericloning. If you tried, none of the offspring will show correct variegation. They will all be solid green or completely albino. However, they are still able to be considered a cultivar because they can still be propagated by division.