Re: Re: Iris abicans

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To expound on this a bit.  The 44 chromosome Iris are technically unbalanced tetraploids.  They have a make up of 8 + 12 + 12 + 12 chromosomes.  They come from a 40 chromosome parent crossed with a 48 chromosome parent (or as Sharon stated, perhaps an unreduced gamete from a 24 chromosome parent).  The 40 chromosome parent is an amphidiploid (also technically a tetraploid, not unbalanced, but with two sets of 8 and two sets of 12 chromosomes - so fully fertile - functionally diploid with two matched sets of 20), and these are derived from a cross of a 32 chromosome parent (or unreduced 16) with a 48 chromosome (or unreduced 24).  So, the plants end up with three sets of 12, and one set of 8.  In the old "wild" 44 chromosome types such as albicans the sets of 12 could all be from one parent species, or from two.  The set of 8 is most likely from I. pumila in all cases, but if from an unreduced gamete could be from one of the 16 chromosome species (it had to contribute 16 to the 40 chromosome parent - only 8 of which make it into the 44 chromosome plants).

 

 

To me it seems most likely that the "wild" ones (albicans, germanica, florentina, etc.) are derived from Near Eastern tetraploids crossed with I. pumila, but these aren't the only possibilities.  The tetraploids were apparently cultivated and carried around by people, or at least this seems the most likely explanation to why they have popped up as "wild" populations here and there (not commonly) up all the way to the west end of the Mediterranean.  These crosses must have been rare, since the wild TB Iris flower so much later than the dwarfs.  Once established though, they seem to have been very successful at surviving.  Seems the 44 chromosome hybrids were more successful as cultivars and at naturalizing than their parent, since they are widespread and common. 

 

The wild parentage thing is all supposition on my part.

 

 

 

Dave