Genetic mapping would be the best way to ID hybrids, but then we'd no doubt
find lots of registered hybrids that were the same, and the "same" ones that
are actually different!

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Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Books, Artwork, and Lots of Free Info!
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"Xi Wang" wrote in message
news:5oI_c.320405$J06.197116@pd7tw2no...
Hi,

Oh I agree complete that my African Queen vs. Lee Koi Choon example does
not give you plants with identical genes, no cross does. This is why I
did not say identical, I said equivalent. There is a lot of variation,
but based on the parentage, it is *theoretically* possible that you could
have one plant of African Queen that is exactly identical to Lee Koi
Choon, although this is not the case in the vast majority of the time. I
mean, no two Violet Charms are the same unless they are clones, and yet
this entire genetic spectrum of plants are all called that simply because
they have the same parentage, and contain half and half of their genes. I
mean, if I gave you an African Queen and a Lee Koi Choon, without telling
you which was which and said here's a DNA sequencer that can tell you what
genes came from which species, but not the exact root it took to get
there, one would most likely conclude that the two specimens should be of
the same grex. I guess once again it is just a convention I'll have to
accept. You raised the point of different genes coming from pollen vs.
seed, which is definitely true much like how mitochondrial DNA is only
inherited from the mother in the human. However, BxC = CxB in terms of
naming with the RHS.....

Cheers,
Xi

Ray wrote:

As to your first point about selfing, you are absolutely correct that the
genetic percentages could be redistributed differently, but remember that
the hybridization of orchids has been going on a lot longer than we have
even known about genetics, so Violet Charm x Violet Charm = Violet Charm,
by convention.

On your second point, I think you're really oversimplifying the genetics,
as it's not just percentage contributions from parent that make the
difference.

Based upon my readings and discussions with folks who really do know this
stuff, (A x B) x (C x D) is very likely not at all equivalent to (A x C)
x (B x D) due to the dominant/recessive issue among others. Look at the
simple A x B cross - offspring can show AB, Ab, aB, and ab gene pairs.
Are they the same hybrid? Yes, Are they "equivalent?" No. Now multiply
that single gene by the total number and the combinations get far more
diverse.

That is also why your African Queen vs. Lee Koi Choon example fails.
Going back to your (A x B) x (C x D) versus (A x C) x (B x D) example,
it is highly unlikely, but entirely possible that the first cross ends up
with genes entirely from A & C, while the second is B & D, which nobody
would argue to be the same. That, however, lends total validity to your
Violet Charm point!

Then there's pollen versus pod parent issues, in which - apparently (so
I've heard) - some genes come almost exclusively from the pod parent...

Hi,

Agreed, but there's an even more troubling issue, which is that two
different plants may actually be grouped into the same grex under this
simplification. There are plenty of 16-20th generation hybrids, which,
if one takes a look into their genes, possess very similar genetic
demographics, and could very well be confused as the same grex if one
were not aware of the crosses with which those genes were assembled. I
have a spreadsheet set up which looks at which crosses were used to make
which plant, and traces the full lineage and calculates the genetic
makeup of a plant. There are tonnes and tonnes of plants with similar
genetic makeups (eg. ~60% amabilis, ~10% amboinensis, ~10% schilleriana,
~10% sanderiana, ~10% stuartiana). They are all different in terms of
the crosses involved, but if you gave them to a phylogenist who had no
knowledge of orchids, he would say they are all the same thing. And I
mean, since orchids breed so easily with one another to give fertile
offspring, how does one really define species, or genera for that
matter. There's one intergeneric which is a mix of 9 'true genera'.

Cheers,
Xi

Ray wrote:

Genetic mapping would be the best way to ID hybrids, but then we'd no doubt
find lots of registered hybrids that were the same, and the "same" ones that
are actually different!

Hi Xi,

Seems that you understand the naming convention and are correct that an
orchid name does not describe an unique gene pool. I have changed your
example a little to remove mitochondrial DNA issues although I did not have
to since AxB = BxA. I agree that [(AxB)x(CxD)] is equivalent to
[(AxD)x(CxB)] although RHS would give them different names.

Ray is correct that making these two hybrid could produce very different
results. As an example, if only A and D carried a recessive albino gene,
the first cross would make some whites while the second cross should produce
none. But since sibbing and selfing does not change the name, sibbing or
selfing the right plants from the second cross would also produce some
whites and still carry the name of the second hybrid. I think the two
hybrid names define exactly the same gene pool. I do not think there is any
genetic combination in the first cross that could not be produced from the
second with selfing or sib crosses. In fact, I think both names define all
of the genetic material of A, B, C, and D.

As you said RHS naming is just a convention we have to accept. The
convention is different than what is used by most of the plant world. For
most of the plant world individual plants being released for sales are named
and the cross they came out of is not tracked. Some of the major cloning
companies have taken this approach to naming orchids and you will sometimes
see plants such as Phal 'Snowapple' for sale. Boy has this made orchid
people scream, but for consumers who knows nothing of RHS it makes more
sense. The labs have been pretty good responding to the screaming in that
most of them will now provide RHS names if asked.

Pat

Xi Wang wrote in message news:5oI_c.320405$J06.197116@pd7tw2no...
(big snip)
I mean, no two Violet Charms are the same unless they are clones.
(snip)

The grex system is not designed to uniquely identify each and every
unique hybrid plant. The ability to give plants clonal names does
that. It augments the grex system to allow you to distinguish between
plants that have identical ancestry but different phenotypes.

The grex system records ancestry, so that breeders can reconstruct the
geneology of hybrids. This gives them some idea how to replicate or
modify a line of breeding. Most other groups of horticulturally
important plants do not follow the grex system. Instead, each unique
plant is given a cultivar name that is published with a description of
the plant. Technically, a plant with completely different ancestry
could be the same cultivar if it meets all the criteria in the
description.

Each system has advantages and disadvantages. In the orchid grex
system, a plant is useless if its ancestry is unknown. With a
cultivar system, a beautiful plant with unknown ancestry can still be
described and used for hybridizing. The key is to write a
sufficiently detail description so that unrelated plants do not fall
into the same cultivar.

Nick
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