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RE: HYB: Daylight Independent

A classification scheme does not have a one-to-one correspondence with

Keeping a record of rebloom and correlating it with temperatures at
night is a good exercise, and may help clarify things.

As far as I know, I'm the first person to use the term "Daylight
Independent Rebloomers" and I used it to describe  Forever Blue and
it's children. They all show  the same anytime rebloom. I don't see any
thing else  except for perhaps Precious Little Pink (IB) that show the
same pattern.

Forever Blue can bloom almost every day  during bloom season, and has
done so for me  in many seasons. Usually there is about 5-7 days
without bloom, at the end of the TB season, and then it starts again.
I havenbt seen anything even close to that in TBs, even with those that
have summer rebloom.

In Southern Ontario, Immortality is one of the first TB to bloom, and
it blooms around May 28th and finishes about June 15th. Rebloom is
about Aug 15th, about 60 days later.  This is the earliest of any
rebloom here on TBs.

To understand rebloom it is first necessary to understand the
mechanisms of bloom. Each perennial has its own pattern and timing
sequence. Rebloom is usually a disruption of normal triggers. I'm
talking biology here and pant biochemistry. For iris, there is  a need
for estivation. An extended cold period  such as winter that sets  next
years  incipient bloom stalk. Changes to the need for  cold weather or
a decreases of  degree of cold for the biological trigger  is probably
one difference between a oncer and a rebloomer. Thus rebloomers can set
a bloom stalk without a winter period.

This winter period is there to prevent a plant from dying  out over
winter, as the rhizome that blooms in the fall usually dies. Rebloomers
are usually also very vigorous and have many increases so that there is
still many daughter rhizomes  that survive over winter.  A compensation
for the rebloom trait  that permits survival. Remove one of these
traits and you don't have a rebloomer. Some plants may have a bloom
stalk set in a  rhizome that has not reached a size large enough to
support a bloom stalk, so it is not triggered to produce bloom stalk.
The bloom stalk also need other biological conditions to be met before
bloom is triggered.  As the rhizome  gains size later in the season,
these other conditions are met and the plant precedes with a bloom

When you get reports of rebloom in July, you also should look at when
spring bloom was.  It probably was at least 60 days or so after spring
bloom finished.

So I'll continue to use the term "Daylight Independent" to describe
Forever Blue and its children as it seems to describe a genetic
condition that they have. I haven't seen anything about Immortality and
ilk that would convince me that they are "Daylight Independent"

The  rebloom from Immortality and Forever Blue are defiantly different
genetic systems, based on result of crosses made between them.  Thus a
different term should be used for this early and reliable colder areas

Chuck Chapman

Date: Sun, 17 Feb 2008 08:58:59 -0500
From: autmirislvr@aol.com
Subject: [iris] {Disarmed} HYB: Daylight Independent

<<There are various biological triggers for flower bloom. >>


For clarification, I'd like to revisit the subject, although it is true
that I
don't care what we call them so long as they bloom when I want them
<humor>? AND . . . I can breed others to do the same.?

For several years now, I've been trying to pin down the cause of summer
bloom so
that I don't send a lot of time breeding things that won't meet my
20 something years, I've wrestled most of the concepts into
submission.? It's
primarily the language that has me buffaloed.?

Maybe it's the term "Daylight Independent" that is throwing me.?

I've been keeping a temperature journal for over a year.? There is
that night time temperatures (along with rain/water) may trigger
rebloomer here
in?June, July & August.? Although I'd really prefer early September for
viewing pleasure.? ?

For anyone that might be interested in hybridizing rebloomers--the same
rules of
gene combining apply as in regular irises, but there are more genes to
take into
consideration--the rebloom genes.? In addition,?rebloom has it's own
and/or triggers.? ?

Basics:? In the new judges handbook it states that there are now 5
types of
rebloom.? It further states that the 1) Cyclic Rebloomers are the
standard for
the rebloom class.? If this is true, many of us will be left out of the
game because they often don't get their act together until it's too
late in?our
colder zones.? For my purposes, these rebloomers are too predictable.?
Maybe, if
they could be modified to bloom earlier??

When a hard freeze hits KY on or around Oct 15, I lose most of my
rebloom.? Not
something I'm willing to tolerate IF I have a choice.?

For several years, I've been looking for irises that summer (July &
bloom, not only for me, but in all zones.? When I find an iris, like
Evening or Pure As Gold,?that blooms in July in both California and
Nebraska, I
figure it's worth taking note.?

The garden reports that have meant the most in my search are Richards
in CA and
Jedlicka in Nebraska.? Both listed their rebloom by month.? It's
their seasons would both be different than mine but the early rebloom
is my

3) Repeaters . . . this class seems (to me) to mature late rhizomes
(not full
grown in the spring) and then bloom when mature.? There is another
involved, perhaps one that regulates rhizome growth,?because they all
bloom at
approximately 6 weeks after the first rhizomes in the clump finish
(Summer Radiance made such a display in early July one year that all
neighbors congregated.?)?

Classifications?2) Multiple Blooming Irises & 4)Sporadic Rebloomers
appear to me
to be the same, with #2 having stronger triggers.?

Classification #2 contains the irises I'd thought to be Daylight
These irises bloom at any time they choose throughout the summer and
fall, from
spring freeze to hard fall freeze.? These irises do NOT need short
daylight days
(fall) to rebloom.?

Chuck, if I'm understanding you correctly, you are saying that these
rebloomers are all REPEATS?? They have a different trigger/modifier for
growth?? There is a distinct difference in the "timing" of stalk
release?in the
two groups.?

5) Secondary Stalk Rebloomers (according to the NEW judges manual),
rare, occur when rhizomes send up secondary stalks in the same growing
I'd thought these to be early REPEATERS.

In summation, we MAY have two classes of rebloomers: 1) cycle and 2)
sporadic?with different triggers??

Again, I speak of TB's only.?

Betty Wilkerson/south central KY/Zone 6--My brain still scrambles on
the words
Allele and Gamete, (I think it's an allergy) but I'm getting much of
the rest.?

- -----Original Message-----
From: irischapman@aim.com
To: iris-photos@yahoogroups.com
Sent: Sat, 16 Feb 2008 1:48 pm
Subject: [iris-photos] Re: Hyb: Daylight Independent

Different rebloomers do different things in different climates.
Immortality is almost always the first of the TBs to rebloom here, but
never before mid August. It does not show any characteristics of
daylight independence for me in my climate and not for anyone else in
this climate. A cross of Immortality X Forever Blue produced a bunch of
dogs, but no rebloomers of any sort.

There are various biological triggers for flower bloom. I've been
collecting some refferences but haven't read any of them yet.
I can't remember how many, but enough to be sure of my observations. I
also had a number of crosses with other relible early and cold weather
rebloomers, all with the same result. Whatever it is with Forever Blue,
it is different then what is causing rebloom with other rebloomers.
The cross with Victoria Falls is the only cross with TB that has
produced rebloom. Most crosses with other SDB rebloomers X Forever Blue
gives the same story. The Exception was the cross with What Again,
which produced 90-100% rebloomers, all of the Daylight independent
type., that is reblooms whenever. They all did not show the very early
rebloom that is characteristic of those that I introduced, Forever
Violet, Blueberry Tart etc.

I have never seen anything from Immortality (or any other TB) that I
would call Daylight independence. The only other plant that shows
similar rebloom is the IB Precious Little Pink.

Iris are generally triggered by the number of hours of daylight ,
coupled with all the other triggers of spring growth. They also need
the cold period to set next years bloom (estivation). Lloyd pointed out
to me that I could get a lot of rebloom that he didn't as I had colder
nights in the summer. This would suggest that a number of rebloomers
can get away with a temperature differential much less then the cold of
a full winter. These plants still seem to need the daylight triggers.
Artificially giving longer daylight (light supplements) will increase
rebloom. Sometimes a plant will have an bloom triggered in a rhizome,
but it will not have sufficient trigger size in spring to set off
bloom, even through it will respond to the daylight hours of spring.
This rhizomes will continue to grow until it reaches size to produce a
flower. This can appear to be daylight independent, but it isn't.
Trigger size is my own concept. It referees to the size of the rhizome
needed to support a bloom stalk, in terms of plant energy. I would
suspect that a lot of rebloomers have a small trigger size.

The hours of daylight to trigger a bloom can be very specific. I once
rescued some daffodils in the spring, just as they were starting to
grow. Some of them went into the garage for awhile . They didn't get
planted for a while, but took off when planted and had extremely good
plant growth and it didn't die off like other daffodils did. Then in
Fall, as the daylight hours decreased, it went into bloom, triggered by
the length of daylight hours.

Forever Blue is an extremely strong grower and it can produce trigger
size rhizomes in a shorter time then most plants. These rhizomes do
seem to need cooler evenings to produce an embryo bloom stalk, and it
does not seem to need a daylight trigger to start this bloom stalk,
only the size and perhaps cooler evenings.

Immortality does seem to need the daylight trigger for the new rhizome
rebloom. This is different then late spring bloom as the stalk was
triggered but rhizome had not reached trigger size. This does not seem
to happen in southern Ontario. Perhaps because of the later spring.
This would mean that the plants have had a bit more time for the
underdeveloped rhizomes to get to trigger size. One of the sine non
quoin of bloom is the ground/air temperature. Plants can grow in colder
temps, but it is needed to set off bloom stalk growth.

Again, I repeat, Ihaven't seen any TB rebloom here in Southern
Ontario that would seem to be Daylight independent. They all rebloom in
corespondence to spring daylight hours. Other people have reported
summer rebloom, but I suspect other reasons. and causes to trigger
rebloom, just not known

Chuck Chapman

Re: Hyb: Daylight Independent

Posted by: "Autmirislvr@aol.com"

Fri Feb 15, 2008 3:56 am (PST)

A few hybridizers are working on this trait in TB
rebloomers.? Constantly searching for irises that bloom in the summer.?

Like other traits it is stronger in some irises than others.?

Chuck, how many seedlings did you bloom from Forever Blue x

Betty W/KY/zone 6

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