Re: REB: aphylla rebloom genes
iris@hort.net
  • Subject: Re: REB: aphylla rebloom genes
  • From: C* C* <d*@rewrite.hort.net>
  • Date: Wed, 24 Dec 2014 15:52:34 -0500
Definitely recessive. That is why we can get rebloomers in a cross of aphylla to something else. Not sure there is a corresponding gene in the iris that are not endo-dormant.
Some other species are reported to be endo-dormant, such as some subspecies of pallidia that are native to mountain regions. .
When we get "collected" aphylla, they each come from an environment to which they have adapted. So daylength will be different for each clone. For me I see them go down about end of October for the clones I have here. Some years they get hit by frost before triggering of endo-dormancy. Then foliage looks like mush rather then nice tidy dried leaves.
I suspect that triggering of dormancy is enabled only after either bud set or maturity, so can't trigger in spring. It is turned off by vernalization, so needs to go through all the biological processes to be reset in preperation for short daylength in fall.
Most iris are eco-dormant in winter. So will grow whenever growing conditions exist. Basically when warm enough. This will vary from cultivar to cultivar. 

Enough for one post. If anything  unanswered,  post another question

Chuck Chapman

-----Original Message-----
From: Linda Mann <101l@rewrite.hort.net>
To: iris <iris@hort.net>
Sent: Wed, Dec 24, 2014 12:42 pm
Subject: [iris] REB: aphylla rebloom genes

Several thoughts/questions about aphylla & rebloom

Chuck, do you know if the aphylla photoperiod response is dominant or
recessive?  Do you know if it is responding to shortening days,
triggered in summer, or actual daylength?  If the latter, any idea what
daylength?
I've been looking at seedling differences in the range of green to brown foliage this time of year, before it gets cold enough to kill foliage to the ground (if it ever does this winter), wondering what happens with an 
aphylla photoperiod winter dormancy cross with something that tries to
grow all winter.

Before I started breeding my own irises, I noticed that the cultivars
that I bought that did the best here usually dropped foliage during
drought and during winter. Pallida tends to also drop foliage in really 
cold winters here, but I've not noticed it in summer.   Discussion on
iris talk way back when concluded that it could be influence of one or
more of several of the diploid ancestors - variegata, pallida, aphylla.
Most of my keeper seedlings (which made it fine through last winters dip 
to zero F with no snow cover) try to put on more green whenever it's
somewhat warm and do not drop foliage during drought. (There's a lot of
seedling selection pressure for drought tolerance/deep root systems.)

I've always suspected there is some aphylla influence in the GPBrown
rebloomers because of the abundant branching, but maybe aphylla isn't
the only source of that type of branching?

Linda Mann
Merry Christmas Eve everybody

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