Iceberg appears to have 2n pollen

I was looking at some pollen from Iceberg today under the microscope and noticed that there appears to be consistently some pollen grains that are large enough to be 2n (unreduced is a term some use). I just stuck some cuttings to get some root tips to check if Iceberg really is a triploid like most of us suspect.

Anyway, Iceberg appears to have some grains of pollen that may have three sets of chromosomes. There are also some pollen grains that are the diameter typical for 2 sets as well as a relatively small amount the diameter typical for 1 set. There are also a lot of aborted grains. However, for a suspected triploid there seems to be quite a bit of well-stained pollen.

It sounds like there are some members that would like to cross hexaploids with diploids to generate tetraploids. Perhaps if one uses a diploid female and put Iceberg pollen on it, one can get tetraploids as a portion of the offspring. It would sure be interesting to use its pollen on diploid species like R. rugosa.

Other triploids (i.e. Nearly Wild) don’t seem to have much if any really large, possibly 2n pollen, which seems to make Iceberg a little bit unique.



This is a very intresting theory David. I have gotten pollen of Iceberg and pollinated with The Fairy. If it is true what you have said, then some or at least one should be a tetraploid.

I’ve also done a foliolosa x Iceberg cross, although only on 4 flowers. It seems that foliolosa is done until next year.

I did the root tip squash yesterday and, yes, Iceberg does have 21 chromosomes and is a triploid.