There are two known paths of inheritence of yellow. the regular yellow
and the "alternatie yellow" which I have spoken about several times.
The regular yellow, production of cartenopid pigments is dominant over
non production of cartenoids. Regular dominant cartenoids are pinks,
regular yellow part of oranges, and yellows, both alpha and
beta-carotene. To get a non yellow we have to have cartenoid production
shut down previous to production of lycopene (shows as pink when not
converted to carotenes). this shut down is a recessive genetic control.
So in order to prevent regular cartenoid production we need four sets
of the recessive reduction of cartenoid genes. Thus when a yelow
(include pinks and oranges here) is crossed with a plant that has no
cartenouids (white or blue) all of the offspring will be yellow,
baring presence of the recessive reduction of cartenoids renes in the
yellow cultivar. Thus all or a significant number of seedlings will
A white with a red beard, such as Shy Fox has four sets of rrC
(recessive reduction of cartenoids). Lady Celestra is also a rrC
cultivar. If there was a yellow underlay, it would be violet or
purple, not blue.
Thus the question of wher the yellow comes from.
Now on to the "alternative yellow" which shows up in orange cultivars
primarily, but also in yellows with tangeringe factor beards.that is
red beards. This yellow is a
recessive, unlike normal cartenoids ,
which are dominant.
Now back to Sly Fox. this has a red beard, which strongly suggests
that it carries the alternative yellow or possible has alernative
yellow plus a repressor of this on petals ( I havn't checked into of a
repressor of alterrnative yellow this, but it is a good possibility).
This all leads to the possibility that Lady Celestra carries the
recessive genes for "alternative yellow". I did a quick check of its
parentage, and didn't see anything obvious.
The seedling you showed was a yellow with an anthocyanin wash over
falls to give its pattern.
Based on the analysis given, if it is an "alternative Yellow" then it
would be a recessive, and unlike regular yellows, (especially in
consideration that it should have four sets of rrC) would produce no
yellows if crossed to a blue, or white. But would produce some
cartenoid plants if crossed to a white with red beard.
To be sure of any of this and provide more information I would need
some numbers. Such as details of plants produced, from say about 10,
possible more seedlings from this cross. This should be enough info to
do a chi-square analysis and be sure of what is happening genetically.
Of course as David says, there can be recessives hanging around ready
to do their thing. But a chi-square analysis should be able to tease
this out, with a enough numbers.
AFor more on "alternative yellow" check previous posts, here and on
Re: HYB TB Photo: SLY FOX x CELESTE correction
Posted by: "David Jewell"
Thu Jul 16, 2009 11:42 am (PDT)
I would have to say that the statments about gentics and what should or
should not apear seem somewhat nieve. While yellow cross yellow have a
higher chance of producing yellow there are no guidelines to say it
must produce yellow. If there were very simple formulas for these
things then everyone would have the perfect iris of the perfect color
and form that we are always looking for.
Genetics be it human or plants are always a crap shoot and can recess
backwards many generations or even make a step forward.
Date: Thu, 16 Jul 2009 14:31:28 -0400
Subject: [iris-photos] Re: HYB TB Photo: SLY FOX x CELESTE correction
I'm very interested in more details of crosses of Sly Fox producing
yellows. If crossed to something that is yellow it would be expected to
produce yellows. But in a cross to something that doesn't have yellow
it should not20produce yellows.
A yellow from Sly Fox X Lady Celeste is a mystery. As reduction of
yellow is supose to be a recessive, none from this cross should have
Ther have been rumours of a dominant yellow repression gene , but no
clear evidence of it's exsistence.
By the way, there is no "dominant White" gene. There is a dominant
repression of anthocyanin gene, but it has no effect on inheritence of