Re: I. sibirica X I. pseudacorus

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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 Barton r*@yahoo.com
*Sent:* Friday, March 04, 2011 4:12 PM
*To:* i*@yahoogroups.com i*@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
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*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