Chromosome doubling and fertility.

I recently read a paper titled

Some roses with doubled chromosomes are fertile (like Basye’s Amphidiploid), others aren’t. It is said that the more sterile the diploid, the more fertile the resulting tetraploid will be, but even fertile diploids can have some degree of fertility after their chromosomes have been doubled. One group doubled the chromosomes of a fertile species rose (R. multiflora) and successfully used its pollen on modern hybrids.

I’ll second what Jim says, I’ve always heard “The more sterile the diploid, the more fertile will be its doubled version”.

And not stated but maybe implicit in that statement, “The more fertile the diploid, the more sterile will be its doubled version”; hence the fertility problems in the rugosa polyploids.

The reason for the fertility problems has been explained as: quadrivalent formation interfering with normal meiosis.

Even though my doubling experiments are still in their initial stages – I can say that it is a lot of effort, as you mentioned. I am encouraged that I’ve even recovered one section of a sterile hybrid, that appears to be permanantly changed in appearance. I’m still waiting for blooms on this portion, so I can’t vouch for its fertility.

I’ll post another message with a link to a previous conversion (on a different hybrid) that has unfortunately died. Below is the link to see the current conversion.

Link: www.koolpages.com/hybridizer/Rose/trifluralin_conversion.html

Here’s the link for the deceased conversion on my rugosa X xanthina hybrid.

Link: www.geocities.com/tesilvers/rugosa_xanthina_chimera.html

Thanks for the feedback.

I had seen Toms rugosa X xanthina hybrid and noted that it wasn

Tom,

I noticed that you used trifluralin (Preen?). Could you share your methodology you used to do the doubling?

Thanks,

Chris Mauchline

SE PA, zone 6