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Re: HYB: rebloom genetics
  • Subject: Re: HYB: rebloom genetics
  • From: Chuck Chapman <irischapman@aim.com>
  • Date: Mon, 10 Jan 2011 21:54:41 -0500

The example you gave of fruit flowers is a good example of facilitative
vernalization. Or as it is sometimes called "Quantitative Vernalization" Thus
when vernalization trigger conditions are not met, you do get delayed
flowering or sporadic flowering. If vernalization gene had been turned off,
they would flower in fall, when photoperiod was appropriate.? When
vernaliation conditions met, they all bloom simultaneously in spring.
This is the same thing as what we get with flowering of the California
rebloomers (facilitative rebloomers), where they bloom after a long time
period between bud set, and flowering. Plant assumes that they have had a warm
winter, and it must now be spring. Without vernalization gene they would bloom
in early fall , like the Fall cyclic ones do.
With? vernalization, it is a recessive gene. Although? there have been
several? alleles of? the vernalization gene discovered in? the ardiposis?
studies. And in wheat studies as well. Some of these? will work together and
some don't. So?? a copy of one vernalization gene in combination with a a
vernaliation allele , could also result in non-vernalization need.
Think? t factor.? One T? will? convert? lycopene to? beta-carotene. A second
third or fourth gene doesn't block effect of T as? to produce lycopene you
need four t genes.?Similarly ?to produce vernalization need? you aparently you
need four matching? vernalization genes.?
?Studies have shown this vernalization gene to be a recessive. Lots of studies
in wheat to determine difference between winter wheat and spring wheat.?
Winter wheat needs vernalization, so must be planted? so sprouts before
winter. Spring wheat doesn't need vernalization, so planted in spring. Lots of
economics here so lots of studies. Whole books written on it.
And other studies show? that vernalization gene? is pretty much the same
regardles of species.
I don't know of any situation of where a dominant gene is no longer
functioning when it is in multiple dosages, unless it is a lethal gene in
multiple dosages. Those exist, and the plant or animal just dies. One example
of this is black Siamese fighting fish. Males with two dosages of black gene
Perhaps someone else knows of a situation where a dominant gene is turned off
in multiple dosages, but I can't think of any off hand.
The case of the petunias. multiple dosages of the dark purple gene (AVI
actually), It now stops working in centre of flower, but colour is still
present on rim.?But is not completely turned off, just severely modified in
appearance. (actually without looking study up, I'm thinking petunia, but it
may have been another garden flower).
Further thoughts. Multiple dosages of dominant amoena gene pushes colour
further out to the rim, and removes it farther from centre of flower, but the
amoena gene is actually removing anthocyanin from standards, so is actually
increasing its effect.
Chuck Chapman


-----Original Message-----
From: Linda Mann &lt;lmann@lock-net.com&gt;
To: iris@hort.net
Sent: Mon, Jan 10, 2011 3:51 pm
Subject: [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
cumulative chilling hours required to break dormancy. Many of the flower buds
still break dormancy, just not all at the same time.?
So back to my original question, can you think of a mechanism where off
wouldn't necessarily be off if it was present in multiple doses? Multiple
copies of the gene might somehow interfere with normal function of the gene??
Maybe something like the petunia color genes that cancel each other out if
they are "matching" sets, where one of either set is purple, but the two
together result in white rather than darker purple (or pink or whatever color
they were trying to intensify).?
&lt;It is an off switch (need for vernalization is turned off)??
It doesn't matter how often it is turned off. Off is off. &gt;?
Linda Mann east TN USA zone 7?
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