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Re: REB: genetics (was Rose Kinnard's seedlings)
iris-photos@yahoogroups.com
  • Subject: Re: REB: genetics (was Rose Kinnard's seedlings)
  • From: Chuck Chapman <irischapman@aim.com>
  • Date: Sun, 14 Nov 2010 11:38:45 -0500

 

Check my article in Spring 2009 rebloomer. I had details on leaf count in there. Each cultivar has it's own mature leaf count. Average was about 11-12. But I found a low as low as 9 and as couple as high as 15.

The last two leaves don't often show until bud set has initiated. The last leave will show as basal leaf on bloom stalk. Leaf scars on rhizome are included in leaf count. These represent leaves that have died, and been cleaned off.

Do any  these people with rebloom have min/max records for their garden, so it can be checked? 

With Sky Queen,  was it rebloom on these clumps , or  initial bloom on different  clumps?

With micro-climates , if min temp in main part of garden hovered around 70, micro-climates could very well  have had bud trigger temperatures.

Also of note, if watering is regular, and at cooler part of day, it can lower temerature enough  to bring apical meristem (which is located about 1/2" above rhizome)  into bud set temperature range.

A  procedure that could be used for people who's temperature  hovers just above bud set temperatures, to initiate bud set and rebloom.

Chuck Chapman




-----Original Message-----
From: Jan Lauritzen <janicelauritzen@yahoo.com>
To: iris-photos@yahoogroups.com
Sent: Sun, Nov 14, 2010 1:21 am
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
Chuck,

You and others have referred to "mature state (as measured by leaf count)".  Can you please tell me the number of leaves a plant must develop in order to bloom? 

All this temperature discussion is interesting to someone here in the San Fernando Valley of Southern California where the nighttime temperature may not drop below 70 any time from April until late October.  And yet there is a lot of bloom here and irises can bloom any time.  Our main requirement is providing summer and fall water as we get so little (read that as usually none) from April until November. 

I had one year when I had at least one flower in bloom EVERY day for one full year.  Frequently, the only one in bloom was 'Sky Queen' which would bloom for me 3 to 5 times per year because I had it planted in different microclimates around the place.

Jan in Chatsworth



From: Chuck Chapman <irischapman@aim.com>
To: iris-photos@yahoogroups.com
Sent: Sat, November 13, 2010 6:49:11 AM
Subject: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 

I don't consider a plant to reblom unless it consistently has two periods of bloom a season, on same clump.

If a plant doesn't bloom in spring, but blooms in July/Aug for you, then that would be initial season bloom for you.

If a plant has had vernalization, but hadn't had  bud set , as plant is not at mature state (as measured by leaf count)  in spring, then it  won't bloom in spring. with other plants. If it reaches maturity slightly after  regular spring bloom then it could very well have the nighttime temperatures to enable  bud set, and thus  initial bloom  after regular season. 

Vernalization is an "Epigenetic"  event. All the cells in the plant are set into a  different state, and are primed  for bloom.   When a plant blooms in spring, the plant and all attatched  plants (increases) are reset to to the "non-vernalized" state, so plants that mature later, and have bud set, now can't bloom until the plant has had a vernalization  reset , by apropriate cool weather.  If there are no bloom stalks on clump, then plant continues in a vernalized state, and  can respond to further biological signals, even if out of normal sequence.

So if one clump of the cultivar blooms in spring, and another clump doesn't bloom in spring, but does so later , this is not rebloom, as on seperate clumps..

Same with a cultivar that gets out of  sequence and bloom only in fall, but has  imature increases that don't bloom in spring.

So for me, rebloom means that the same clump, can, and does relatively consistently, have two bloom periods (or more) per season.


Chuck Chapman

-----Original Message-----
From: Betty Wilkerson <Autmirislvr@aol.com>
To: iris-photos@yahoogroups.com
Sent: Sat, Nov 13, 2010 7:28 am
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 

<<That is initial bloom out of season.  Not rebloom.>>
Chuck, are you saying that every time something blooms in June, July, August & Sept. in my climate it is not rebloom?  And the same is true for the CA gardens that get summer bloom? 

<< plant will only do this the once. After that it is synchronized with environment and plant controls.>>
 
I'm guessing you are referring to individual rhizomes and not to the cultivar?   So, it's possible that a cultivar could have a trait where it typically doesn't reach maturity in time and blooms in the summer? Like my 'Summer Radiance?'  Then an increase could inherit the trait and do the same thing?  So, in theory, you could have a clump that "appears" to rebloom regularly in the summer, but doesn't fit the "definition" of rebloom? 
 
 
 
Thanks,
 
Betty . . .
 

 
-----Original Message-----
From: Chuck Chapman <irischapman@aim.com>
To: iris-photos <iris-photos@yahoogroups.com>
Sent: Fri, Nov 12, 2010 11:46 pm
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
I have had this on many an occasion, and it had been reported by many people.

That is initial bloom out of season.  Not rebloom.

Several possible explanations, but plant will only do this the once. After that it is synchronized with environment and plant controls.

Chuck Chapman




-----Original Message-----
From: Betty Wilkerson <Autmirislvr@aol.com>
To: iris-photos@yahoogroups.com
Sent: Fri, Nov 12, 2010 6:32 pm
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
What is responsible for the seedling that bloomed 2 stalks beginning July 18?  Then, I had six cultivars (mostly seedlings) that started bloom in August.  Night temperatures didn't drop below 70 F until the last week of Aug.  (for the required six consecutive nights.) 
 <<As you didn't get this condition until fall, this will be your limiting condition.>>
I understand that this is what triggers the fall cycle.  Since it didn't limit the ones above, I'm wondering why the irises that are capable of doing the same, did not do so.  They should not be limited by the need for falling temperatures! 
 
 
Betty W.
KY zone 6
 
 


 
-----Original Message-----
From: Chuck Chapman <irischapman@aim.com>
To: iris-photos <iris-photos@yahoogroups.com>
Sent: Fri, Nov 12, 2010 8:27 am
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
You can't get rebloom until there is bud set. That depends on temperature, ie 6 nights with min 59-68F. (of course variations around this average) As you didn't get this condition until fall, this will be your limiting condition.

I suspect ph is a minor concern.

Chuck Chapman


-----Original Message-----
From: Betty Wilkerson <Autmirislvr@aol.com>
To: iris-photos@yahoogroups.com
Sent: Fri, Nov 12, 2010 8:41 am
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 

<<Triggering for Fall cyclic and Summer rebloomers needs proper environmental conditions.>>
Chuck,  I knew that I had high night temperatures.  There were few nights below 70 degrees (F) all summer--over two months.  None with six in a row. I didn't expect much bloom on the cycle rebloomers (fall.)  I did hope for bloom on the summer rebloomers, or early fall rebloomers, since I watered them through the summer.   
 
As Colleen has stated, I think my problem may be ph adjustment. 
 
Betty Wilkerson
Zone 6-KY
 
 
 
 


 
-----Original Message-----
From: Chuck Chapman <irischapman@aim.com>
To: iris-photos <iris-photos@yahoogroups.com>
Sent: Thu, Nov 11, 2010 10:48 pm
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
Triggering for Fall cyclic and Summer rebloomers needs proper environmental conditions.

Need to be a leaf count maturity, and in environmaent sutible for growth. Plus  6 nights in a row with  minimum temperature between 15-21 C or 59-68F.

Also can't be in dry or heat dormancy.

Check you temperature records for summer.

Chuck Chapman


-----Original Message-----
From: Betty Wilkerson <Autmirislvr@aol.com>
To: iris-photos@yahoogroups.com
Sent: Thu, Nov 11, 2010 12:04 pm
Subject: Re: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
 
<<A plant can have genetics for rebloom, but not rebloom in  a certain climate as environmental conditions  are not suitable, or more  likely secondary genetic  factors in combintion are not suitable to trigger rebloom for that climate.>>
 
This seems to be the case in my garden for sure.  Many of the irises that are reputed to be very good rebloomers all over the country, haven't been happy in my current garden.  Even this year, with altered conditions the rebloom was very limited.  There were many wasted stalks on plants that, theoretically, should have bloomed much earlier.  It could have been the results of the two months with the relentless high & low temperatures for two months, but I have a feeling there is something more.  Maybe the secondary needs? 
 
We may need a reminder of the secondary genetic factors/needs you speak about.  Are we talking modifiers here?  Soil condition may be as important as climate.   

<<There are four genetic systems for rebloom.  (From what I can tell at moment) These are all different , and don't sem to be complemetal or cumulative. So they don't add to each other. >>
 
I seem to remember you stating that some are dominant over others.  You don't believe two or more rebloom genes can transfer to the same plant?  (Just restating in a different form.) 
 
Can we recruit some new rebloom hybridizers?  Any takers out there?
 
 
Betty W.
Zone 6
 

 
-----Original Message-----
From: Chuck Chapman <irischapman@aim.com>
To: iris-photos <iris-photos@yahoogroups.com>
Sent: Thu, Nov 11, 2010 9:59 am
Subject: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
If the "preferntial Rebloomers" have a long enough growing season in your climate, then they would rebloom in your garden.

I have noted some more northern gardens that can do this. But they have a long growing time between last frost in spring and first hard frost of fall.

To tell if you climate is suitable for this type of rebloom, grow some of these plants. Don't count any fall bloom in year of acquisition. But again, in colder areas, they will likely be racing against frost.

There are four genetic systems for rebloom.  (From what I can tell at moment) These are all different , and don't sem to be complemetal or cumulative. So they don't add to each other.

But secondary  conditions are additive. That is , rapidity of growth, low leaf count maturity, wider temperature range for bud set, fast increase, lower temperature for cold dormancy, higher temperature for heat dormancy , drought tolerance, earlier bloom time , tolerance of crowded conditions,  etc..

So these secondary factors can be added from combining differernt genetic rebloomers (or from any other plant having these secondary genetics). But still only earliest rebloom trigger will  give you  rebloom.

A plant can have genetics for rebloom, but not rebloom in  a certain climate as environmental conditions  are not suitable, or more  likely secondary genetic  factors in combintion are not suitable to trigger rebloom for that climate.

Lloyd Zurbigg found this. He  made a lot of rebloom crosses here in Canada, but had little sucesse. When he moved to USA, these same seedlings rebloomed for him.

Chuck Chapman



-----Original Message-----
From: Linda Mann <lmann@lock-net.com>
To: iris-photos@yahoogroups.com
Sent: Thu, Nov 11, 2010 6:29 am
Subject: [iris-photos] Re: REB: genetics (was Rose Kinnard's seedlings)

 
I'm not convinced yet that in my long growing season some of the
"summer" bloomers here don't also have what you are calling preferential
vernalization genetic makeup.

Plus I thought that there are multiple genes contributing to rebloom?
So it's not just presence/absence of a particular type of vernalization
requirement. Are you positive it's a different gene and not just a
different suite of max/min & duration of temperature requirements?

Takes a lot of crosses to answer that question, I think.

Most of the CA and Oz (and esp OR) rebloomers are in what is more or
less zone 8, close enough to my zone 7b temperatures. Now if we can
just combine wet/humid enthusiasm with their dry summer/low humidity
selection, and if all the other genes that contribute to rebloom match up...

I agree that it seems unlikely to work for you that far north, Chuck.
Wait for global warming? ;-)

> Final Episode seems to be one of those iris that rebloom when it has an extended period of warm weather while in a mature state. A class of rebloomers that are basically "prefernial vernalization" as versus "Obligatory vernalization".
>
> Obligatory vernalization means that the plant has to have vernalization before blooming. Preferntial vernalization have a secondary sytem, that enables it to rebloom when it has had a long period while sitting at maturity. These types will rebloom in Australia and California, but not else where.
>
> So breeding with it will perhaps produce California rebloomers, but unles you live in a climate that has an apropriate long warm growth period, it won't contribute much to a rebloom program.
>
> Chuck Chapman

Linda Mann east TN zone 7b USA




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