Re: Re: REB: rebloom seedlings
iris@hort.net
  • Subject: Re: Re: REB: rebloom seedlings
  • From: C* C* <d*@rewrite.hort.net>
  • Date: Mon, 6 Oct 2014 11:15:09 -0400
Progress in good form on rebloomers for cooler climates has not progressed much, if any since Clarence (Zurbrigg, 1991) . That is 23 years ago. It is still the best formed flower that consistently reblooms for me. At time it was said "Rebloomers are now come of age" . Since then on goal for people breeding rebloomers was to get flowers equal to best of oncers on rebloomers. Two routes were taken.
1) Breed strong cooler climate rebloomers to warm climate rebloomers with great form. 

2) Breed rebloomer s to each other and select best form etc.

Neither of these approaches have worked.
What I'm offering is a reason why they don't work, and an approach that I strongly feel will give progress. Now that I'm finally getting TB iris that are super hardy in my very challenging climate I can now work on reblooming TB iris. I expect that they will never perform up to my Whenever SDB iris which seem to bloom in all climates, down to zone 2B, as well as much warmer ones. I haven't found a pathway to bing the "Whenever" rebloom genes into TB. Stil lworking on it, but suspect that it just isn't possible.
There is a lot of literature on blooming triggers in the scientific literature. A very complex dance of genes. Many many different genes involved. The only one that can produce rebloom only in warm climates are ones associated with a process called "facilitative vernalization" A protective measure for warm climate species that enable it to bloom in spring when it doesn't get winters cold enough to trigger vernalization genes to provide correct signal. A backup system, so to speak. So it blooms after a period of growing conditions equivalent to five months after bud set. Warm climates give a longer growing period then the Mediterranean species get in native habitat, so thus bloom out of season. So if an iris only reblooms in zone 8 and 9, as far as I can see this is the genetics it has.
As this is an ongoing study, learning as I go, I'm always interested in hearing of something that would suggest that is not so. Then I can relook at the information and look for other reasons. 

Chuck Chapman

-----Original Message-----
From: Linda Mann <101l@rewrite.hort.net>
To: iris <iris@hort.net>
Sent: Mon, Oct 6, 2014 9:36 am
Subject: Re: [iris] Re: REB: rebloom seedlings

Which assumes that is possible/easy.  Easy to use the former, but I got
nowhere trying to do the latter <here> because they wouldn't produce
viable pollen.

The "most productive choices" needs the caveat of "for your breeding
conditions".

I don't like your assumption that all 'sporadic/mediterranean
etc' expression of rebloom = proof of the presence of one type of
rebloom gene.

i.e., my 'bet' is that it isn't always just one type ;-)

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