Why is Cym Imogene Coca so apparently warmth-tolerant?

[MrCym]

One would expect a Cym hybrid with 75% genetic influence from Cym. grandiflorum to be heat-hating yet this hybrid blooms year round in Colombia and seems bulletproof. It cannot be the 25% Cym. pumilum genetics surely? Maybe Cym. grandiflorum is much more complex a species than I thought? I was told by an old eccentric in Christchurch that it was grown in NZ for Mother's Day cut flowers and if the plants were a little backward, it would take added heat at night without any problems. As I lived in the semi-tropical North Island, we used to dread hot daytime weather in April as Cym. grandiflorum would just sulk and never open its blooms. Hybridizing can often lead to questions rather than providing answers!

[Gary S]

It is good to see that a hybrid every so often will throw out a heap of questions and it is also good to see that some questions will remain unanswered. Otherwise hybridizing would be all too easy, if every cross turned out to be everything the hybridizer wanted.

It would be interesting Andy, to learn what percentage of all your crosses actually ticked all the boxes you might have had in place when planning the cross. I am betting the percentage would be surprising!

[Australis]

It could also be a trait that only appears when certain genes are combined; e.g. hookerianum may not have warmth tolerance on its own, but carry enough genes for it that when paired with something that has the missing pieces, warmth tolerance is then exhibited. In my experience, we often think of traits as been controlled by an individual gene, but in reality that is not always the case. Then there's epigenetics on top of that (effectively which parts of genes are switched on or off, which increases the complexity even further).

[MrCym]

Interesting but I've never thought of Cym. pumilum as imparting warmth-tolerance. Apart from Imogene Coca's clear parental influences, I would be more likely to expect say Cym. ensifolium X Cym grandiflorum to exhibit significant WT qualities..... Such a hybrid exists, originator unknown, and has an AOS HCC but no available photo. It of course has done nothing since the award in 2009 and primary pumilum hybrids have a reputation for infertility in their diploid iterations anyway.

[Australis]

Cym. ensifolium X hookerianum = Pink Butterfly

Photo here: viewtopic.php?p=32399

Cym. floribundum does seem to survive heat, based on reports from a couple of growers I know.

[wolfman]

The underlying question to all this is: is there a gene, a gene complex and / or chromosomal locus that imparts &
controls “warmth tolerance” to orchids, and is it for all species & hybrids the same gene(s) or loci controlling warmth-tolerance?

I scanned a number of databases for the subject - and absolutely nothing came up. There is not even scientific work published that correlates warmth tolerance with genetics; so far we don’t even have proof for the mindblowingly simple question: is there a gene for warmth-tolerance ?

Very baffling, if anyone has literature on the topic he / she could copy me on that would be terrific !

[Australis]

Unfortunately, Florian, I am unaware of any such study! Considering that most orchids have yet to have their full genome recorded, I think it would be a big job to determine a conclusive answer to that question.

My personal hypothesis is that it is not a single gene that controls warmth tolerance, as there are likely multiple factors involved that determine a plant's survivable temperature range.

[MrCym]

Well l have a long experience with Cym. pumilum. It blooms early April/October in cultivation But its spikes are visible well before the Winter Solstice. What happens with its F1 progeny is that they spike and the spikes continue to develop normally. The bulk of pumilum primaries bloom by late Spring. We no longer use it in any hybrids but remain aware of its invaluable genetic influence.