Re: Re:HYB:Glaciatas/green pigment
- To: i*@egroups.com
- Subject: Re: [iris-talk] Re:HYB:Glaciatas/green pigment
- From: J* C*
- Date: Thu, 30 Nov 2000 02:34:53
>Crossing a glaciata to a non plicata would be like crossing a plicata >to a
>non plicata, except even worse. You would then have to work very >hard at
>bring plicata back in and even harder to bring glaciata back >in.
Not having done a lot of hybridising, I don't speak from personal
experience, but my understanding of genetics tells me that this is not so.
The alleles that can exist at the 'plicata' locus, from what I have read,
are:
PL - the allele for solid colour, dominant to all the others
pl - the allele for the plicata pattern
plu - the allele for the luminata pattern, neither dominant, nor recessive
to the plicata pattern
pla - the allele for the glaciata pattern, recessive to all others
If you cross a plant which has pla pla pla pla (a glaciata) with a plant
which has solid colour, you could get any of the following combinations:
PL PL pla pla
PL pl pla pla
PL plu pla pla
PL pla pla pla
but each seedling will have at least 2 pla alleles. When crossed back to a
glaciata, the average percentage of glaciata seedlings produced will be
25%. Another 25% of the non glaciata seedlings will have 3 alleles for pla,
and the rest will have 2.
If crossed back to a sibling, an average of at least 1 in 16 seedlings would
be glaciata, i.e. 6.25%
Depending on what other alleles the solid colour plant was 'hiding', you
could get other patterns. Studying the ancestry of such cultivars would help
considerably.
The idea that you would have to work through the plicata pattern to get to
the glaciata pattern is what I can't accept. Clearly the glaciata has no
plicata allele's present, and if it is never crossed with a plicata, or a
solid coloured cultivar, with plicata genes present, then there would be no
need whatsoever, to 'work through' the plicata pattern to get to the
glaciata. Line breeding should bring the glaciata pattern back fairly
quickly.
Cheers, Jan Clark
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