Rosa acicularis

Could anyone explain to me the differences in ploidy between the North American and Asian rosa acicularis. Modern Roses XI simply lists ploidy as (28, 42, 56). I am very interested in using it in breeding, and if anyone has experience with it, or has info that may be helpful, I would greatly appreciate your input. Last summer I crossed it with Rosa nitida pollen. The cross produced a lot of seeds. I am hoping for fertile offspring to use in crosses with garden roses.

Mark Disero, Brantford Ontario, Canada

There also is a 14, 28 form - R. acicularis Nipponensis. I show pictures of what I think (hope) is the 2 forms at:

http://home.neo.rr.com/kuska/R.acicularisnipponensis.htm

In the past I have distributed open pollinated seeds of what I think is the 28 form to others.

I did not collect any this year, if you are interested I can check to see if the birds have left any hips on my bush.

Link: home.neo.rr.com/kuska/R.acicularisnipponensis.htm

This is an almost unexplored area.

About distribution: polyploids often grow also (not only) outside the diploid’s geographic and/or ecologic range. From a more varied chromosome complement they may have more adaptation possibilities. Polyploidy may be (not allways) a shortcut for different but not compatible (at diploid level) adaptations to be instantly brought together. In northern areas, polyploidy is more frequent.

About how? From personal communications (published??) ploidy may be controled by the cytoplasm. That is if cytoplasm favor haploid gametes then diploidy is the rule. There are probably cytoplasms that favor diploid and/or polyploid gametes or that do not favor (from lost hability?) haploid ones and allow or favor polyploidy.

Does anyone know regardless of the ploidy of the specific subspieces, if rosa acicularis divides it septets evenly between egg and pollen (egg= 3n, pollen= 3n) or assymetrically (egg= 4n, pollen= 2n)? I have been unable to find this info.

Thanks

I believe it is only the Caninae section roses that have irregular meiosis. I’m pretty sure R. acicularis divides evenly.

Joan