Re: REB: HYB: rebloom breeding
iris@hort.net
  • Subject: Re: REB: HYB: rebloom breeding
  • From: C* C* <d*@rewrite.hort.net>
  • Date: Thu, 27 Nov 2014 09:07:27 -0500
In terms of Preferential vernalization rebloomers, is that the 5 months of growing conditions after bud set is the INITIAL trigger to remove vernalization need and to reset epigenetic state. So plant is now in the vernalized epigentic state. So after that plant will rebloom frequently during next season. And the plants that have not been set into vernalized epigenetic astate will not rebloom until late in season, but will be set for next season, and so on. This state will carry over to a new climate for the first year of growth, and then will be set by it's new environment. So you could get "rebloom' first summer in new environment. After that it will settle into a response to it's new environmental signals. It needs the 5 months (give or take) to get the vernalized epigentic state, bypassing regular vernalization. After that it is good to go.
The early bloom you see in spring on rebloomer is usually from the Fall cyclic rebloomers that were triggered the previous fall and then went into eco-dormancy ( that is too cold and daylight too short for good plant growth). So next year have a head start. If you observe these clumps with early bloom you will see some flower stalks at normal bloom time and in some years no early spring bloom.
As there different types of rebloom genes are all involved in different points in flowering gene complex, they are independent and could all be present in any one plant.
The Fall cyclic rebloom genes are a dominant condition. In terms of inheritance. In combination with Preverential vernalization genes, it will dominate. So if present, plant will rebloom in colder climates.
Fall cyclic with Instantaneous ( summer rebloom ) genes, the instananeous will control. Immortality is a good example of this. As far as I can tell it has summer as well as fall cyclic genes.
In a combination of Instantaneous and PV (preferential Vernalization) genes the Instantaneous will dominate.
To tell which gene is controlling rebloom you need to have good environmental data and plant observation. Thus I keep records of minimum and maximum temperatures and correlate this as to went plant s rebloom. When in doubt, I consult my temperature records for the few weeks before bloom. 

Chuck Chapman


-----Original Message-----
From: Linda Mann <101l@rewrite.hort.net>
To: iris <iris@hort.net>
Sent: Thu, Nov 27, 2014 8:29 am
Subject: Re: [iris] REB: HYB: rebloom breeding

That's too restrictive - I'm in zone 7, Betty is zone 6, not sure which
Mary Lou is - zone 6 I think.

I refuse to believe that my reblooming seedlings are an illusion! ;-)

On 11/26/2014 8:32 PM, Chuck Chapman wrote:
The preferential ( warm climate rebloomers) have nothing to offer me, 
or
most breeders of rebloomers who do not live in a zone 9 area. It is 
an

illusion for anyone not in a zone 9 (perhaps not for some zone 8).


One more question - if an individual cultivar/seedling has preferential
rebloom genes, is it possible for it to also have a set of recessive
rebloom genes plus a set of cycle rebloom genes?

Assuming the answer is yes, let's see if I got this - in our zone "9"
breeding programs, we are combining preferential rebloom genes (some of
which also may or may not have recessive rebloom genes and/or dominant
fall cycle genes) with cold climate tolerance (all of which have either
recessive "summer" or dominant fall cycle rebloom genes).

With added cold tolerance (resistance to light freeze damage), these
seedlings have a longer potential season to do the preferential rebloom
thing, if the season is just right in zones 6-8.

The 'real' zone 9 (CA/OZ) rebloomers that can bloom in July would have
to have bloomed in ...5 months earlier would be Feb, so more likely
these bloomed in late fall - Nov/Dec.  & the ones that bloom in Aug
would have 'spring' bloomed in March.

Do TBs start blooming in Mar in zone 9?

Is this where the idea came from that to get rebloomers, it's best to
cross the really early blooming ones?  Never have been able to
understand the logic on that one - those are the ones most likely to be
frozen out, here anyway.

So that 5 months thing would make cycle rebloomers pretty
indistinguishable from preferential rebloomers here - first bloom in
April/May, 5 months later is Sept/Oct.  And in colder zones, they are,
not surprisingly, reblooming in Nov.  Some of these are very reliable
rebloomers in parts of zones 6 & 7 where late freezes aren't an issue.

Thanks Chuck, I think I understand some more about what might be going
on with some of these occasional rebloomers that I'm getting. plus it
makes some sense out of the ones that try to rebloom in late OCt/Nov
here. I am definitely going to have to start irrigating to sort out the 
seedlings that may be cycle/preferential vs the recessives that I want.

Tho it may not be of any use to you or others in zones north of 6, the
ability to grow well enough to be a reliable preferential rebloomer with 
good form and fertility is a good thing.  Not a first generation
rebloomer of the genetic type I want, but will have some of those genes
in the first generation and a decent probability of recapturing them in
the next generation.

Have a good Thanksgiving, Chuck!

And Happy Thanksgiving to everybody else as well.

;-)

Linda Mann

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