You do not mention which group of orchids you are interested in. Since you say 'intergeneric', it can't be slippers, but almost all other orchids are in play. I am not aware of any publication on these issues.
It is generally something breeders learn by experience (and from their peers). It is obviously dictated by genetics, but few breeders have truly analyzed their results into something that logically follows the laws of genetics.
Considering that genetic dominance does not apply equally to reciprocal breeding**, it is impossible to condense this subject into a few clear rules. Let me give you some examples to illustrate this:
(Asctm ampullaceum, var alba x Neofinetia falcata) = Ascofinetia Cherry Blossom.
- This cross produced only pink colored flowers, since the alba version is recessive, and the white Neofinetia falcata was a standard white. Thus, the NF cancelled the white from the Ascocentrum.
- There might be some recessive white NFs out there, but I don't know how to recognize them among the standard white flowers.
- On the other hand, if we self pollinated the Cherry Blossom, we should get 25% white flowers in the next generation.
All albas are recessive, but not all albas are the same genetic mutation. An example of this is found in the brachypetalum sub-group of Paphiopedilum. Most of these 'whitish' Paphs have some light speckling. Then you have the alba varieties, which have no antocyanin based pigment. However, in Paph bellatulum the alba mutation is different from the other Brachys, so (bellatulum alba x niveum alba) produces flowers with spots.
Neofinetia falcata is fragrant (at night). When bred, there is usually no fragrance in the next generation (even when the other parent is fragrant). Sometimes fragrance comes back in the following generation. I can't even begin to analyze this issue genetically, as it would require breeding two generations in multiple configurations, keeping all the seedlings and record results for each plant.
** Finally, trait dominance differs depending upon which plant carries the seed pod. One of my favorite intergenerics is Neostylis Pinky = (Neofinetia falcata x Rhy gigantea). I have quite a few of these, and it is very obvious that:
- RG x NF is 3 times the size of NF x RG
- RG x NF flowers have fairly broad segments, while NF x RG flowers are star shaped.
I have seen similar results in Renanetia Sunrise (Renanthera imschootiana x Neofinetia falcata).
- RI x NF has stubby leaves, while NF x RI has long slender leaves.
- RI x NF has Renanthera shaped flowers, while NF x RI has star shaped flowers.
Hybrid Mode
