Expected ploidy in breeding with Canina or hexaploid Alba as pollen parents

These are presumptions I would like to get some feedback on. I’m maybe totally wrong here. In standard Canina meiosis the pentaploid parents would combine like this:
1n=4x7 (seedparent) x 1n=1x7 (pollenparent) => 2n = 5x7

So I presume if using a Canina as father, you can consider him to act like a standard diploid? When crossing a tetraploid with a Canina as father you would have a high chance in getting a triploid, as you would with a tetraploid x diploid cross?

What about a hexaploid Alba like Semi-plena? Would this one act like a triploid? Giving both 2x7 and 1x7 pollen? If used as a pollenparent in a cross with a tetraploid, could I expect to get tetraploid offspring?

I’m considering working with an Alba to get some specific traits that are hard to find in other roses. I don’t want to end up in the Canina mess, so I’d use them as fathers only.

Corrections or confirmations to my assumptions would be greatly appreciated.

Seems to be the general consensus, based on various posts read over the years.

Only difference is likely albas act more as tetraploid than triploid, so tetraploid x alba should generally result in tetraploid…

You may be interested in Rolf Sievers various Blush (Crimson Blush, Lemon Blush, Red Blush, Royal Blush, etc there’s like a dozen of them) roses, see if any of those have the traits you’re looking for. While the first gen are once blooming they produce reblooming offspring which possibly saves you time and headaches.

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I published a review paper that may be of interest. it is available online: 'Small' and 'Great Maiden's Blush' and other Alba-Hybrids : Thor Landsverk : Free Download, Borrow, and Streaming : Internet Archive


Thank you. Very clear and interesting. For English speaking ppl: page 30 to 44.

Thank you Thor!! What a wonderful resource on the diversity of Alba roses. I think pollen diameter is a nice tool to estimate the ploidy contribution of the male parent. ‘Alba Semiplena’ and ‘Maiden’s Blush’ had pollen in the range of what would be expected from 2x pollen in the low 40’s for uM.


It would be interesting to follow pollen diameter over generations using Albas in crosses (both as female and male parents) to see when and how things change for Caninae meiosis.

The great grandfather of Petite Pink is an open-pollinated seedling of ‘Applejack’. It is a seedling of a friend and she suspects the male parent was ‘Alba Semiplena’ since it was growing next to it and the seedling has some features that look like ‘Alba Semiplena’. I wonder how much of the wonderful health and nice foliage may have been contributed to that breeding line from Albas.

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