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Re: Re: HYB: rebloom genetics
iris@hort.net
  • Subject: Re: Re: HYB: rebloom genetics
  • From: Chuck Chapman <irischapman@aim.com>
  • Date: Tue, 11 Jan 2011 08:52:00 -0500

Good question.

Both? dominant repression of Anthocyanin (dominant white as it is sometimes
called) and dominant amoena are both of what are reffered to as contol or
regulator? genes.? That is they act to control? the function of other genes,
ie: those that produce anthocyanin,

The genes that produce? the pigments(are involved in chemical conversions in
chain of producing the pigments)? are called? functional or structural genes.

When you have a recessive white,? (we are not talking of the glaciata white in
this example)? you have four defective genes that are unable to produce the
enzyme needed for the next stage of anthocyanin production.? If you have one
of the four genes (in a tetraploid)? that can produce the enzyme ( a
structural gene)? then you have anthocyanin.

A control gene can operate in several ways.? One way is to block action of?
the structual gene. And there are a few differernt ways this can be done.

Another way is by producing an enzyme that (in this case)? converts the
anthocyanin into a colourless? form.

A white from a dominant white (I is designation used for this gene)? has
anthocyanin as a colourless pseudobaxe (leucoanthocyanin) . This can be
converted to a visable normal anthocyanin with the adition of a strong acid,
eg: hydrachloric acid.

To me this sugests an active production of an enzyme that converts anthocyanin
into leucoanthocyanin.? Although it could be argued that? it is an enzyme
which prevents? the initial conversion of leucoanthocyanin into
anthocyanin..(blockage)

But we do have? incomplete supression, as what we get with Ae (anthocyanin
enhancement)?? and very light blue? cultivars where there is incomplete
supression? of anthocyanin production.

And we do have the cumulative effects? of Is.? Which shows increased
supression of anthocyanin over larger areas with increased number? of Is
enes.

But the basic and honest answer, is we don't really know.? I choose to see it
as a removal, as a concept it makes it easier for me to keep a handle on how
it works.?? But it very well may be a blockage.

Take your choice as to how you view it.

Chuck Chapman





-----Original Message-----
From: Betty Wilkerson &lt;autmirislvr@aol.com&gt;
To: iris@hort.net
Sent: Tue, Jan 11, 2011 8:05 am
Subject: Re: [iris] Re: HYB: rebloom genetics




&lt;&lt;the amoena gene is actually removing anthocyanin from standards, so is
actually increasing its effect.&gt;&gt;

Is it removing it or blocking it?  Would it matter?


Betty W.




-----Original Message-----
From: Chuck Chapman &lt;irischapman@aim.com&gt;
To: iris &lt;iris@hort.net&gt;
Sent: Mon, Jan 10, 2011 9:02 pm
Subject: [iris] Re: HYB: rebloom genetics


The example you gave of fruit flowers is a good example of facilitative
ernalization. Or as it is sometimes called "Quantitative Vernalization" Thus
hen vernalization trigger conditions are not met, you do get delayed
lowering or sporadic flowering. If vernalization gene had been turned off,
hey would flower in fall, when photoperiod was appropriate.? When
ernaliation conditions met, they all bloom simultaneously in spring.

his is the same thing as what we get with flowering of the California
ebloomers (facilitative rebloomers), where they bloom after a long time
eriod between bud set, and flowering. Plant assumes that they have had a warm
inter, and it must now be spring. Without vernalization gene they would bloom
n early fall , like the Fall cyclic ones do.

ith? vernalization, it is a recessive gene. Although? there have been
everal? alleles of? the vernalization gene discovered in? the ardiposis?
tudies. And in wheat studies as well. Some of these? will work together and
ome don't. So?? a copy of one vernalization gene in combination with a a
ernaliation allele , could also result in non-vernalization need.

hink? t factor.? One T? will? convert? lycopene to? beta-carotene. A second
hird or fourth gene doesn't block effect of T as? to produce lycopene you
eed four t genes.?Similarly ?to produce vernalization need? you aparently you
eed four matching? vernalization genes.?

Studies have shown this vernalization gene to be a recessive. Lots of studies
n wheat to determine difference between winter wheat and spring wheat.?
inter wheat needs vernalization, so must be planted? so sprouts before
inter. Spring wheat doesn't need vernalization, so planted in spring. Lots of
conomics here so lots of studies. Whole books written on it.

nd other studies show? that vernalization gene? is pretty much the same
egardles of species.

 don't know of any situation of where a dominant gene is no longer
unctioning when it is in multiple dosages, unless it is a lethal gene in
ultiple dosages. Those exist, and the plant or animal just dies. One example
f this is black Siamese fighting fish. Males with two dosages of black gene
ie.

erhaps someone else knows of a situation where a dominant gene is turned off
n multiple dosages, but I can't think of any off hand.

he case of the petunias. multiple dosages of the dark purple gene (AVI
ctually), It now stops working in centre of flower, but colour is still
resent on rim.?But is not completely turned off, just severely modified in
ppearance. (actually without looking study up, I'm thinking petunia, but it
ay have been another garden flower).

urther thoughts. Multiple dosages of dominant amoena gene pushes colour
urther out to the rim, and removes it farther from centre of flower, but the
moena gene is actually removing anthocyanin from standards, so is actually
ncreasing its effect.

huck Chapman



----Original Message-----
rom: Linda Mann &lt;lmann@lock-net.com&gt;
o: iris@hort.net
ent: Mon, Jan 10, 2011 3:51 pm
ubject: [iris] Re: HYB: rebloom genetics
Trying to think creatively here, not that I think it would be true.?

Off" isn't always off - thinking of fruit tree buds that don't get the
umulative chilling hours required to break dormancy. Many of the flower buds
till break dormancy, just not all at the same time.?

o back to my original question, can you think of a mechanism where off
ouldn't necessarily be off if it was present in multiple doses? Multiple
opies of the gene might somehow interfere with normal function of the gene??

aybe something like the petunia color genes that cancel each other out if
hey are "matching" sets, where one of either set is purple, but the two
ogether result in white rather than darker purple (or pink or whatever color
hey were trying to intensify).?

lt;It is an off switch (need for vernalization is turned off)??
t doesn't matter how often it is turned off. Off is off. &gt;?

inda Mann east TN USA zone 7?

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