Re: fertility of mixed crosses with aphylla based iris

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Sterling and Vicki;

            What aroused my interest was the suggestion that ?Arrival? was a tetraploid SDB. I am not sure what is really meant by that use of the term. Has someone actually counted? The term tetraploidy has at times in the past been used in reference to the SDBs  because they have 4 sets of chromosomes. 2 sets are like pumila and 2 sets are like TBs. Most of the time this is referred to as amphidiploidy. The second part of Sterling?s remark  was that it produces fertile hybrids with TBs. Normally an amphidiploid when crossed with a TB produces a IB with an unbalanced set of chromosomes (3TB and 1pumila set). Often these are not completely sterile but certainly fertility is reduced depending on what they are crossed with. It seemed that Sterling was implying that ?Arrival? would have 4 sets of chromosomes compatible with TB?s. If that is true then it is really a TB with the size and form of an SDB. Such a plant could be very valuable as a source for reducing size and creating IB?s and BB?s but if it is truly tetraploid  in this sense, than it would not be especially compatible with other SDB?s. But if crossed back to pumilas it might have a great potential for creating MDB?s with a SDB genotype. Unfortunately I am still not sure how the term tetraploid is being applied. To be able to comment with some authority one would either have to count chromosomes or perform many crosses. Only a couple crosses are not strong evidence since as i said it is possible to have some fertility in an unbalanced genotype.

Vicki Craig <vicki_c@comcast.net> wrote:

Robert,
Earlier you expressed a wish to know of the fertility of the aphylla
derivitives crossed with SDB's. Just thought I would let you know that
the seedling (AHD12L2) pictured  here is a cross between Bouquet Magic
(48C TB) X Pele   (SDB).
I now have pods set on this iris with one of our 48c seedlings and it
also has pollen. When I get the chance i will check to see if I tried to
use the pollen.
Vicki



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