Hi

Also lets remember that soil pH may also be a factor. A lot of rebloomers are raised on alkaline soils. However there a few that seem more likely to rebloom on acid soil.

Colleen Modra
Mt Pleasant 
South Australia

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<<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.>>

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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?Â

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We may need a reminder of the secondary genetic factors/needs you speak about. Are we talking modifiers here?ÂÂSoil condition may be as important as climate. Â

<<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. >>

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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.)Â

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Can we recruit some new rebloom hybridizers?ÂÂAny takers out there?

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Betty W.

Zone 6

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

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

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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