On Sat, 22 Mar 2003 07:42:27 -0500, "Ray @ First Rays Orchids"
(Ray @ First Rays Orchids) wrote in Message ID
:

I have heard of that being done, with the idea being that you'll get some
plants that have genes from both pollen-parents (A&B) with the pod parent
(Z), or (A+B) x Z. It had nothing to do with the health or vigor of the
plant carrying the capsule.

It would be interesting to know the results of such an intended
breeding program. The mechanism that would permit genetic material
from three (or more) gamete cells to combine is nonintuitive. Are you
aware of the existence of any literature, that might explain such a
convenient phenomenon? By what means would the chromosomes pair in an
(A+B) x Z cross? Would this chromosome pairing occur as the pollen
tubes descend the column (pistil/style) toward the ovule, or in the
ovule itself? Fascinating.

However, I think Mick is correct. On the assumption that [if] the capsule
"takes" in the first place, the progeny will most likely be A x Z, B x Z,
or some of each

That is what I would intuitively expect.

I would also expect the usual variations of germination-rate/viability
among the individual crosses of a polycross much as would ordinarily
occur if they had happened in separate overies/capsules. I doubt
polycrossing would have any influence on crosses of incompatible
species, aborted crosses, or production of sterile seeds.

and you'll have to wait and sort them out.

Right. That is the downside to polycrossing: the time and resources
necessity to bloom the crosses in order to identify them. However, if
the breeder's initial intent was to grow-out the crosses to facilitate
flower based selection, I see little difference from unicrossing.

[If] I recall correctly (that assumption gets more suspect by the day...), an
ovum can only be fertilized by a single "male" gamete. The instant there is
penetration of the cell wall, chemical changes make fertilization by another
impossible.

That is my understanding also. So, if the information you recall
hearing regarding (A+B) x Z crosses occurring in a single capsule is
correct, the A+B combining must take place during the time the male
gamete genetic material travels the pollen tubes. But that begs the
question of polyploidy.

Thank you for your contributions to the discussion of this topic, Ray.
They are most welcome.