Re: Re: HYB: REB: Genetics of rebloom
iris@hort.net
  • Subject: Re: Re: HYB: REB: Genetics of rebloom
  • From: C* C* <i*@aim.com>
  • Date: Tue, 22 Mar 2011 11:48:26 -0400
 Pure as Gold has rebloomed here as a summer rebloomer for the past two years.
This summer in two diferernt clumps, located in differernt iris beds. I think
others have reported summer rebloom from it. But I'll give a cravat with this.
I saw summer bloom, but can't honestly sayB  that I had seen it bloom in
spring, so may have just been summer bloom, and not rebloom.

So the natural question is, did Lullaby of Spring bloom in spring? Only report
of rebloom has been zone 8/9. This question crops up often. That is when we
see out of normal season bloom, it is sometimes hard to remember if that same
cultivar bloomed in spring, so is it a rebloom or is it delayed bloom.

"Facilitative rebloom" is the term used for a plant that can bloom without
vernalization, ifB  conditions are right. Blooms earlier with vernalization,
but given right conditions can bloom without. A long growing season, after bud
set, say 4-5 moths can provide these conditions. So a plant that reblooms only
in zones 8 or 9B  is very likely ofthis type. So a very normal condition.
Unlike Fall Cyclic, that is are combination of dormancy and vernalization
gene, and Whenevr and Summer rebloom which may very well be mutations in
normal bloom "supression" genesB  which are ther to prevent out of season
bloom, which are normally a waste of plant resorces.

For me, this is a very specific trigger of fall bloom, and I don't include
sporatics from outsideB  these ag zones in clasification of Cal rebloomers.
I'm tying to classify rebloomers by the specific genetic controls ofB  their
out of season bloom. This is my way of trying to understand rebloom and to use
this information in breeding. So general sporatics, are not necessarily
facilitative vernalization in their genetic control, so grouping in this
classificationB  would defeat my purpose.

When you look atB  weather in a lot of California and OZ locations, it is hard
to see that these locations can get enough cold weather to getB  proper
vernalization. Remember the Utah model of vernalization? Get chill units for
each hour between 34-40 F and lose chill units for each hour above 60F
(simplified for convenience).

Some plants from warm climates show good cold hardiness. They are the ones I'm
using. If they don't grow well in my climate I'll use them only if no other
choice for colour or pattern, and then only as pollen parent.

Earlier Bloom Trigger: I have noticed that once bud set has been initiated in
main fan, that the increases start to grow.B  The main fan seems to suppress
growth of increase until bud set is initiated. As fall progresses, some TB
will have some cultivars with increases with much larger size then others.
This suggests that these cultivars have set bud initiation earlier then other
cultivars. Perhaps at a lower temperature then others, or perhaps with fewer
days at bud set temperatures. This year in fall, while taking garden
inventory, I made note of these cultivars. I plan on using this information in
selecting cultivars to use in rebloom breeding. It will also be useful in
selecting plants to breed for cold climate hardiness. The reasoning on this,
is that a lot of plants fade out over time in cold climates as they have
problems with bud initiation before winter, and thus donbt have increases to
carry on plant into following bloom season. And thus slowly fade out with
time, as eventually no increases to carry on.

Chuck Chapman





---- Original Message ----
From: Linda Mann &lt;lmann@lock-net.com&gt;
To: iris@hort.net
Sent: Tue, Mar 22, 2011 10:05 am
Subject: [iris] Re: HYB: REB: Genetics of rebloom

   A few different ideas in this thread - just to clarify a bit.B 
B 
 When I say "CA rebloomers", I mean what I think the handbook calls  sporadic
rebloomers.  In particular, I mean irises that may not  originally come from
CA, but rebloom in ideal growing conditions esp in  CA/OZ.  In particular, the
kind of CA rebloom I'm curious about is the  kind that occurs in Jul/Aug in
CA.  Some examples I've heard about  include LULLABY OF SPRING and PURE AS
GOLD.B 
B 
 Curious about what would happen to seedlings of these mixed with super  tough
Zurbrigg lines in my growing conditions.B 
B 
 Otherwise, Oz/CA genes appeal more for the patterns, colors, and form.  If
they are prolific rebloomers there, that's nice, and would love it if  those
genes can contribute something to rebloom, but that's not the  reason for
trying to use them.B 
B 
 Linda Mann east TN USA zone 7B 
B 
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