Re: HYB: pigments

The recessive amoena is a separate "epistatic" (external enzyme system
affecting expression of another synthesis product differently
determined) from "blue" anthocyanin production, which it affects by
establishing a distribution over the fall surface layer--the umbrata
spot pattern.

The pattern may occur on a white (RRA) flower, a blue one, yellow one or
any combination thereof.  It can also occur together with the Cook
Progenitor amoena dominant amoena factor, which it overlays on the
surface, the dominant affecting the entire fall petal, at least the edge
border (as in Kerr's varieties--the Emma Cook pattern) and the base of
the standards, even its most extreme forms except those that approach
the Emma Cook extreme expression.

The white spot around the beard in the anthocyanin form does appear in
irises carrying plicata genetics, and may be related, or not.  There are
possibly more than one white spot type as well, as the ones with the
round form (Shoop's amoenas such as Last Laugh) seem different from
those with the triangular expression (various Schreiner blues, etc.).

I think it may also occur together with expressed plicata (example: the
luminata-amoena with spot, Clarence).

The white spot with carotinoid pigments may be entirely unrelated if it
is pigment distribution based.  If, however, the spot is a product of
some factor determining something about the cellular structure
disallowing pigment expression of *all* types (oil-based yellow, water
soluble yellow, violet-blue) then it would (or could be) one factor or
chain of factors with a single end expression.

I think the pigment-destribution interpretation of the spots is more
likely, as it can occur in *either* or *both* or *neither* pigment types
separately--example of yellow with white spot plus violet self is seen
in those rose colored blends with violet flash below beard.  The yellow
has a white spot, the violet does not.

Neil Mogensen   z 7  Reg 4  western NC mountains

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