Re: I. sibirica X I. pseudacorus

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Sean,

there are a few know exceptions, such a I. pseudacorus 'Gubejin', which is compatable with I. ensata, due to aneuploidy. There must be others, maybe right in our own gardens, waiting to be noted and used. I need to spend some time picking Tomas Tambergs brain. He has an amazing amount of experience and a very analytical approach to hybridising.

Yeah, amphidiploids have a lot of advantages. Certainly, one gets a mixed cytoplasm and, theoretically, one could breed toward a universal cytoplasm that allows for higher fertility within the genus. The problem is doing a proper analysis. Possible, technically, but I would think too pricey for the most of us. :-(ÂÂÂÂÂÂÂÂÂÂ

Still, possibilities wing the soul, don't they.

-- 
Jamie V.

_______________________

KÃln (Cologne)
Germany
Zone 8 

Am 05.03.2011 22:45, schrieb Sean A. Zera:

Interesting. Presumably a lot of barriers are selected for to prevent  
hybridization in the wild, where sterile offspring are usually dead  
ends. I wouldn't be surprised if there's enough variability among  
irises that some genotypes might turn out to be compatible among  
species that typically can't cross.

Another possibility that occurs to me is that some amiphidiploids  
might cross more easily or widely than straight species, if they  
express a mixed phenotype say, closer to the average cytoplasmic  
makeup for iris.

Sean Z



Quoting "JamieV." j*@freenet.de:

Sean,

I had thought the same, but, apparently the tetraploidy doesn't make  
the plants more compatable that the diploid version, simply allows  
them to reproduce into another generation.  Not all genetic barriers  
are understood.  It may well be that there are exceptions, but I've  
not found any records of them.  One main reason for incompatability  
is the cytoplasm of the seed parent not being compatable with the  
pollen.  Regardless of ploidy, a viable embryo is not possible.

Maybe someone with more knowledge in embryo viability can shed some  
more light.

Jamie V.

_______________________

KÃln (Cologne)
Germany
Zone 8




Am 05.03.2011 20:10, schrieb Sean A. Zera:

I sort of assumed that interspecies crosses between tetraploids would
actually be easier to produce. In a diploid cross, enough of the
parents' chromosomes have to be sufficiently analogous to pair, or the
embryo will be inviable, not just sterile. In a tetraploid cross, this
is irrelevant because each chromosome has a compatible twin of its own
species to pair with.


Sean Z



Quoting "JamieV."j*@freenet.de:

Jim,

using tetraploids will give amphidiploid offspring, which will be
fertile.  Diploid hybrids often have unbalanced chromosomes and fail
to produce viable gametes during meiosis and are thus infertile.
The advantage lies in the next generations as most diploid
wide-cross hybrids are dead ends.  As to whether the actual cross
will be easier to make, I doubt it, but one has a better outcome for
the extra effort to get the cross to take.

-- 
Jamie V.

_______________________

KÃln (Cologne)
Germany
Zone 8



Am 05.03.2011 00:51, schrieb g*@sasktel.net:

Now this is all very fascinating information for one who likes to
do some hybridizing!  Canât wait to give it a try myself.  Also,
will look forward to seeing this hybrid seedling flower as well.
I do have a question regarding the use of the tetraploids â why
would this work any better than using both diploids?  Also, it is
interesting that if siberica and sanguinea are not closely related
that the offspring from such a cross as still quite fertile??
Jim in Saskatoon
*From:* Rodney Bartonr*@yahoo.com
*Sent:* Friday, March 04, 2011 4:12 PM
*To:* i*@yahoogroups.comi*@yahoogroups.com
*Subject:* Re: [iris-species] I. sibirica X I. pseudacorus

My understanding is that Siberian Irises, as a class, are mostly I.
sanguinea. A surprising finding by Dr. Wilson is that I. sanguinea
is not very closely related to I. sibirica.

Rod
------------------------------------------------------------------------
*From:* JamieV.j*@freenet.de
*To:* i*@yahoogroups.com
*Sent:* Fri, March 4, 2011 3:54:21 PM
*Subject:* Re: [iris-species] I. sibirica X I. pseudacorus

Dennis, et al,

I've tried the cross a few times with no takes, but using
tetraploids should most certainly work creating an amphidiploid.
There are quite a few tet sibericas to try.  Sultan's Ruby comes to
mind as being a very reliable garden plant.  Dennis, could you send
over some of the tetraploid pollen?  I have SR and a couple of
other tetraploids in the garden.  This may be worth a try.

Jamie

Am 04.03.2011 22:47, schrieb Dennis Kramb:

I grow both.  I can try it this year (if you remind me!).
Actually my clone of pseudacorus is tetraploid, so that could
improve chances of a successful cross.

Dennis in Cincy

-- 

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-- 
Jamie V.

_______________________

KÃln (Cologne)
Germany
Zone 8

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