Re: Re: HYB: REB: Genetics of rebloom (was orange)
iris@hort.net
  • Subject: Re: Re: HYB: REB: Genetics of rebloom (was orange)
  • From: C* C* <i*@aim.com>
  • Date: Sun, 13 Mar 2011 19:46:30 -0400
Here is an extract from an article I'm writing

"The temperature trigger for bud set  is same for  FC, Summer and  Cal
rebloomers. Whenever rebloomers are different in this characteristic. That is
about 6 days with minimum temperatures  between 15 -21C (59B:-72B:F).
Following this bud set, the triggers for growing this incipient bud into a
flower stalk is different. A plant can sit at a mature state (as determined by
leaf count on a cultivar by cultivar basis) and not grow, but does not have
bud set until appropriate temperature conditions.

Summer rebloomers grow this bud into a flower stalk immediately, no resting
period or further trigger. Referred to a s a direct bloomer.

Fall cyclic and California rebloomers need a further trigger.

For California rebloomers this trigger is a certain amount of time in bud set
stage. Seems to be about 5-6 months. Basically the plant is using a back up
system developed by plants originating in a Mediterranean climate. Sometimes
it isnbt cold enough in a Mediterranean winter for a proper vernalization,
so if they have a long time a maturity, plant assumes they must have already
had a winter. In a Mediterranean climate this works well, but when moved into
a warmer climate (South California and South Australia) where they have longer
growing seasons, these signals no longer work the same way. Forgive my
anthropomorphism here. The actually term for this is process is facilitative
vernalization. Consider this a dominant gene.

California rebloomers are basically normal plants. That is, no new genes or
gene combinations involved in their rebloom.  A normal trigger, that operates
differently then how it does in the Mediterranean climate where it evolved.
When grown in a climate with a longer growing season,  then where it evolved,
it gets triggered into bloom in the fall, when itbs genetics tell it that
should be  in a  spring following a mild winter."

By nature of climate you grow California rebloomers in yoiu can't make
selection for cold hardiness. And by nature of the genetics, they originate
from warm climate plants. So as you select for earlier bloom, you will very
likely also be selecting for less cold hardiness.

I just don't think Ca Rebloomers  will ad anything to other rebloom genes.
But  there could be a gene interaction.   Others will have to do these
experiments and report on result.

But as FC genes act as a dominant, it will be tough to get anything  that you
could for sure say is an effect from Ca Rebloom genes. And in process  you may
be getting  less hardiness

Chuck Chapman








---- Original Message ----
From: Linda Mann <lmann@lock-net.com>
To: iris@hort.net
Sent: Sun, Mar 13, 2011 7:49 am
Subject: [iris] Re: HYB: REB: Genetics of rebloom (was orange)


Thanks for the clarification, Chuck, and for the update on what you are
thinking about how this all works.

I know you didn't mention CA bloomers, but as I was typing, that's where the
logic took me.

<I didn't mention  the California rebloomers.>

Luckily several of us trying to do just that, making crosses in adverse
climates with selections from OZ & CA.  So there should be lots more data
eventually.

<I'm beginning to suspect that  we could  bring rebloom from Ca rebloomers
earlier into season by selection.  But not likely able to increase plant
hardiness unless these are trialed and selected in more adverse climates.>

Can you say a little more about your thinking?   Do you think these two genes
are the same and maybe interact with other growth genes that differ (i.e.,
temperature thresholds, clock time to maturity etc) or ...

<The  summer rebloomers and Whenever rebloomers seem to be a recessive gene
combined with at least one dominant gene.>

IMMORTALITY is a puzzle as far as passing on rebloom here.  & judging from how
few registered offspring it has, I suspect it's a puzzle for others as well,
given that it seems to be "the" rebloomer that reblooms just about everywhere
on the planet.  I haven't really tried to use it for that much yet, but really
did expect to see more than just one rebloom seedling from it X MATRIX, since
both are summers here. The cross wasn't all that strong, & last year was
maiden, so maybe this year will yield a clue or two.

Not sure how IMM behaves elsewhere, but here it gets carried away producing
increases rather than blooming.  Low stalk to fan ratio, which it passes on in
about half the crosses.  Usually the ones happiest in my growing conditions.
It's a "fault", but I wonder if it is somehow related to IMM's ability to
bloom so often here.  I'm still amazed that one clump of it bloomed last
August during heat and drought.

Linda Mann east TN USA zone 7

---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE IRIS

---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE IRIS
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index