Re: Re: HYB: diploid - tetraploid crosses

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An interesting question. Some of the literature on plant Physiology
may have some good information.

A speculation is that the pollen tubes of the diploid pollen are
larger and probably more vigorous then their monoploid brethren. At
least the pollen tubes would be larger and have more of the cell wall
precursors and be better able to dissolve tissue as they grow down the
style. In tetreaploids the style will be longer then diploids, so
farther to go, so many monoploid pollen grains may not be able to go
the distance.

Just some speculation.

Chuck Chapman

--- In i*@yahoogroups.com, Bill Chaney <billchaney@ ...> wrote:
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>
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> Since I have not seen any posts for a couple days, thought I would
ask a question I have been pondering for some time. These winter days
give me time to poke around the web and do a little on-line library
research.
>
> I am also cross posting to iris-photos and iris-species. If that is
not appropriate, my apologies. I am new to both groups. My
observation is that iris-photos seems to be mostly TB breeders and the
iris-species group has a somewhat wider interest. Is that accurate?
I know many of you will get this twice. Sorry.
>
> So my question is: In making crosses of diploid and tetraploid
plants, my understanding is most people use the diploid pollen on
tetraploid pod parents because some of the pollen cells may be diploid
(unreduced) giving rise to viable tetraploid seed. There seems to be
some good evidence of this happening in the literature in a variety of
plant groups. (One of the advantages of being emeritus from the
University is that I still have electronic library access.) So what
happens to the all the reduced pollen? Does it germinate and produce
pollen tubes, but just not result in viable gametes? In some cases I
know triploid plants are produced, but these seem uncommon in iris.
Is that true? Any suggestions for some good cold night reading on the
subject?
>
> Thanks
> Bill
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