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Re: HYB: umbrata (was Romantic Evening) (long)


I will try to respond both to Linda Mann's and Bill's comments, questions, and
undoubtedly add at the same time to the confusion.

First let's look at 'Romantic Evening' as it appears to the eye without
pre-supposed interpretation.

The standards are lighter than the falls, a good, rich violet color.  The
beard is a dusky red, and the falls almost black from some angles, dark purple
from others.  What haft marks there are are few and about the color of the
standards as I recall.  The photo on Denise Stewart's Snowpeak website is the
most accurate for color I have seen published, and is taken from above the
flower.  The reader might find the following clearer if that photo (thanks,
Denise) is consulted.

Now, theory.  Linda, as I understand those to which you applied having a
characteristic you called by the term "Umbrata"--we're talking about
anthocyanin-pigmented amoenas, variegatas, neglectas and bicolor blends.  In
all the cases the fall has a large, dark area, often with a band surrounding
it the color of the standards, more or less.

Outcrosses from 'Romantic Evening' and its bitone/bicolor seedlings give a
fair percentage, usually about half, with the same dark area of the falls,
often with a band, some without.  This pattern behaves (and does so also in
diploids and relatives of amoenas) as a dominant factor generating a fall
overlay of anthocyanin pigments darker than the standards.  'Dominion' as a
first generation tetraploid from asiatic tetraploid crossed with European
diploid shows this same pattern.  This is very visible in the HIPS photo.

In the outcrosses to selfs, at least in the second generation of 'Romantic
Evening' offspring, the fall overlay ends up around the beard as a whole lot
of veins of dark color with no color or standard color between them, on the
same order of diploid variegata crosses, but rarely to the same extreme.

Since in my own crosses in which this is being observed *no* other source of
the Umbrata characteristic is present, it must by default be coming from
'Romantic Evening.'  Here is one example (no photo, sorry)-- Happenstance X
(Swingtown x Romantic Evening)--medium yellow with scruffy, poorly laid on,
uneven fall blush of dull rose becoming a series of lines around the beard.
Same thing with pink, instead of yellow.  Another--a clean self of light rose
violet.  Another-- a yellow with a white fall, yellow band, no overlay at
all.

That last, the yellow with white area ('Joyce Terry' pattern) is a function of
yellow genetics and can occur with or without Umbrata--no genetic connection
necessary to explain, maybe.  I'm not sure. The band of yellow around white
occurs, or can occur, on the inside of the standards and the top side of the
falls.  That sounds to me to be entirely independent of Umbrata genetics, as
no Umbrata pattern occurs on the inside of the standards.  (Some of the sports
of 'Honorabile' may cause one to wonder about that interpretation, however.)

Resulting assumption:  'Romantic Evening' has, visible, the Umbrata
characteristic which it passes on as a dominant; with distributions like those
of a one-dose dominant. At least, in seedlings from it crossed with a self I
see this to be true.  I'm not sure about dosage level in RE itself.

Consider Wabash, where the recessive character of the *white* is
expressed--the back side, underside of the falls is white, even though with
the translucent character of iris petals the fall overlay does show through as
a sort of shadow.  Crosses out from classic amoenas and variegatas have the
same fall overlay, but rarely on clean, white or yellow basic petal color.
The dark area lays over the other color, whatever it is.  'Romantic Evening'
is like that--the outside of the bud (the back or underside of the fall) is
not almost black.  Once the fall drops, the overlay color is visible.

The presence or absence of the "I-sub-s" inhibitor, 'Progenitor'-derived,
mostly--as in 'Whole Cloth,' 'Kevin's Theme' and Kerr's banded yellows and
whites--is a weak dominant that shows strong variation depending on dosage,
reducing anthocyanins dissolved in the vacuole of the cell most strongly
expressed in the top of the standards and most weakly in the band around the
edge of the falls.  Mid-range dosages can give sharp "amoenas" (redefined to
include these bicolors from what the word meant in 'Wabash' days).  What these
are  genetically consist of (1) selfs of blue or violet-blue, and at the same
time (2) cv's carrying one to four doses of the "I-sub-s" inhibitor preventing
expression of the violet or blue in a gradient from top to bottom of the
flower.  Those that carry one or two doses only will give half or one-quarter
straight, un-modified selfs in the seedlings, the remainder showing some
degree of surpression (actually, diversion to something not visible) of the
blue or violet color.

This is rather more complex when pigments from *Iris aphylla* are present.
These may not be affected--or not affected as much or in the same way--by the
Progenitor factor *or* the inhibitor that makes for Dominant Whites.'

Since a seedling from (Great Gatsby X Romantic Evening) gave a seedling with
near-white standards and rich blue-violet falls, I am assuming both GG and RE
contributed one dose each of "I-sub-s." Near white standards do not appear
with one dose of the dominant amoena factor alone.  The published pedigree of
GG does not support it having the factor.  The visual appearance of it,
however, does and its progeny require that interpretation.

A cross of that seedling described above with 'Wild Wings' which has black
falls, dark plum standards, gave seedlings with almost black falls and violet
blue standards, black falls with almost white standards and so on.

This is why I attributed "I-sub-s" to 'Romantic Evening.'

I sure hope this is being helpful......

In the case of Umbrata, the pattern or spot is an add-on, not a lack of, and
applies only to the surface of the fall.  The band that may or may not be
present around the Umbrata pattern is simply a result of the Umbrata not
covering that band.

In the case of the "I-sub-s" dominant amoena factor, the factor acts as a lack
of, not an add-on.  The underlying reality of such amoenas is a blue (or some
such) self.  The genetic switch involved in "I-sub-s" acts as a turn-off or
preventer of the blue or violet that is present, beginning at the top of the
standards.  Those that have only a band around the fall edge are the extreme
expression of the "turn-off" of violet or blue-generating genetics.

The problem is--both Umbrata and I-sub-s can (and do) appear in the *same*
varieties.  A wonderful example is 'Mastery.'  It also has yellow, an entirely
different issue.  The color of the band around the fall is a separate issue
from the Umbrata overlay present.  The contrast between the fall band color
and the standards has nothing to do with the Umbrata.  It is due to I-sub-s.

I am sure I have added hopelessly to the confusion.

I also want to remind the reader(s) that I am mindful of the title of an
autobiography of a southern Episcopalian bishop, *Frequently Wrong But Never
in Doubt.*  Please understand me--I am full of opinions that I believe to be
correct.  Belief does not *cause* reality however.

Neil Mogensen   zone 7  western NC mountains

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