Any Genetic Difference in which Pod Parent Plant you Choose?
 

Is there any genetic difference in which Phalaenopsis you choose to be the pod parent? So, if you have two Phals and you cross pollinate the two with the other's pollen, will the outcome of the progeny be different?

There's a lot of hand waving and glossing over some details here, so bare that in mind.

During fertilization, each plant contributes half its genes to the cross. As long as both plants have the same number of sets of chromosomes, called ploidy, there will be little to no discernible difference at a population level in terms of the genetics between offspring from using one plant as the pod parent versus using the other plant as the pod parent.

However, the egg from the mother is the sole donor of mitochondria, which are the cell's metabolic power stations. Mitochondria are basically symbiotic microbes themselves, and even have their own DNA. As a result, the mother plant exclusively provides 100% of the mitochondrial DNA to a cross. So, when you consider that, then yes, at a genetic level, the choice of pod parent does make a genetic difference.

With the right tests, and assuming the two plants you chose are from different maternal lineages to begin with, then it's possible to discern between a cross using one plant as the pod parent compared to a cross using the other plant as the pod parent.

It's basically a matter of 2 sets of DNA to consider: The plant's DNA and its mitochondrial DNA. The plant's DNA isn't going to differ substantially at a population level regardless of which parent is chosen as the pod parent. The mitochondrial DNA does, assuming the two plants have different maternal lineages.

I never thought about the mitochondria DNA as being a factor when crossing. If the two plants do have different maternal lineages, will there be a larger percentage of offspring that will contain the mother's characteristics?

Essentially all the mitochondria of all living organisms come from the female parent. On rare occasions one, or a tiny number, might come from the male parent if something goes wrong during spermatogenesis.

Well, you asked about genetic differences, so I kept my first response mostly to that. Phenotypic differences? That's a whole other level of ambiguous complexity. LOL The most concise answer I can come up with is "It depends."

Selection of the pod parent can influence a plant's general vigor, growth rate, vegetative size, and even to an extent things like floriferousness and flower quality. In practice, the differences are generally minimal if discernible at all. Sometimes breeders will make specific choices about pod parent based on vigor or plant size with the expectation that the offspring will be more likely to take after the pod parent in those regards. Presumably that hunch works out sometimes as a direct result of the pod parent's mitochondria (and thus mitochondrial dna).

Very interesting. Yes, you answered my question. Thank you.

If the two "pod" parents are the same species or same hybrid, they are VERY unlikely to have identical DNA (infinitesimal probability), and considering the bell-curve distribution of traits, you're going to end up with a LOT of different offspring.

Certainly, SOME of them might look similar, but there will be some wildly different offspring, as well.

Apart from the DNA issues discussed above, there can be considerable differences between AxB and BxA. For example:

• Cattleya Horace 'Maxima' is known to impart good shape to it's progeny, but it tends to be recessive in terms of color dominance.
• The same applies to Paphiopedilum Hellas 'Westonbirt'.
• When you cross Paph insigne with Paph villosum (= Paph Nitens), the pod parent strongly dominates the flower shape, but the colors are always identical to Paph insigne.
• In a different branch of the orchid family, I have seen a lot of Vandachostylis Pinky (formerly Neostylis Pinky), which is the cross between Vanda (Neofinetia) falcata and Rhynchostylis gigantea. When Vanda falcata is the pod parent, the plant is tiny (4-6" NS) and the flowers are star shaped. When Rhy gigantea is the pod parent, plants are much larger (8-10" NS), and flower segments are much wider.

I don't know much about dominant traits in the Phalaenopsis group, so I can't give you examples there.

I remember a lot of my genetic diagrams in University with recessive and dominant traits. Unfortunately with all of the hybridization, "pure" traits may be buried and it would be a lot of work to re-invent the wheel.