Re: RE:HYB pink genetics

--- In iris-talk@y..., neilm@c... wrote:
> --- In iris-talk@y..., irischapman@n... wrote:
> > I'm currently looking for information re the genetics of pink..."
>
> Chuck, on the violet pigment, you have one too many letters, by the
> way.  There's no "r" in "antho..."   Re the genetics of pinks, there
> are several interacting factors.  One--the production of a carotene,
> normally yellow, that is a dominant, and shows dosage effects. A
> single "Y" produces, usually, a light yellow or cream.  Increasing
> the dosage is one of the means by which yellow becomes deeper
> colored.  There are other factors co-acting usually also.
>   Distribution of the yellow (the pattern) appears to be governed by
> a couple--or more--other factors.  There is more than one carotene in
> irises, I think, and there are yellows that are not converted to
> pink, but the particular carotene that may become pink instead of
> yellow is converted with a recessive "epifactor."  At least that was
> the interepretation at one time of how this works.  This particular
> carotene is converted to a lycopene pigment, the same as tomato red.
> In tomatoes, I believe, the factor is dominant.  In iris it is not.
>
> The presence or absense of anthocyanin violet/blue pigment is
> complex.  There is a dominant inhibitor (I), a selective inhibitor
> that affects standards, the influence most strongly present at the
> top of the flower and progressively weaker the lower in the standard
> one looks, and the falls much less or not at all affected.  The
> result would be pink standards (with some violet flush in the base of
> the standards) and violet falls.  That one was primarily introduced
> into modern bearded irises through the work of Paul Cook and his
> hybrid Progenitor.
>
> The lack of anthocyanin can also be due to a recessive absense of the
> pigment.
>
> The distribution of the violet pigment also may be governed by the
> presence of plicata alleles of various sorts.
>
> Pink x pink does not give ALL pink in all crosses, but in many, the
> seedling count may be too small to reveal the violets that might (or
> might not) be possible.  If both parents are duplex for the
> inhibitor, very few violets will appear in large progenies.  I
> believe that triplex "I" does not often occur.  The speculation has
> been made that the factor may be lethal in more than duplex level of
> the four possible...  I have not seen recent work in this matter.
>
> Pink x violet (with tangerine beard) will give theoretically half
> pink, half violet if the pink has one dose of "I."  If two, five of
> six of the progeny will be non-violet, one would be violet
> (theoretically).  Distance from the centromere makes some difference,
> and whether or not tri- or quadri-valent associations occuring during
> meiosis also can be a factor in seedling ratios.
>
> Is this helpful?
>
> Regards,
> Neil Mogensen    7a in western North Carolina

Thanks Neil, I'm aware of all these factors. What I'm struggling with
is, Is the reduction of anthyocyanin due to the dominat gene or the
recessive genes? Theory suggests the dominant gene, but I have my
doubts based on my own experience and was trying to get data from
other peoples experience. Counts/results of crossess that would help
to differentiate this and to identify any pinks that are definatly one
or the other. I suspect that both types are out there, but theory
needs to meet experience for confirmation.


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