Genetics of doubleness?

I have been looking for info. on the genetics of doubleness but have been unable to find anything up to date. I remember reading up that it was polygenic and possibly dominant genes are involved.

Debener of Germany has an article that came out a few years ago and at this years ASHS meetings a couple weeks ago Dr. Byrne and his student confirmed Debeners findings with another population.

Doubleness is due to a dominant gene. If the rose has the dominant allele of the gene for double flowers, then other, minor, genes can act in the expression or degree of doubleness. Morey and others years ago also address this issue. A few years ago in the RHA newsletter I wrote an article summarizing what I could find on this topic. Roses supposedly have five true petals and then the other “petals” are petaloids, or converted stamens.

Many of our modern roses are not homozygous for the double allele, so we can get a lot of single roses segregating from double parents. For instance, Carefree Beauty has one copy of the allele and four for single flowers. So in crosses with a single rose, for instance, there should be half double and half single progeny.

Are you more interested in breeding for a particular degree of doubleness? Hope this information helps.




I have a difficult cross between a single species and a double rugosa. Out of about 10 seedling of the F1, one is double (15 petals). I am hoping for about a 20 petaled F2 if I sib cross. Would the singles perhaps still be able to affect the degree of doubleness?

Could you possibly email me a copy of your article? I got the paper Debener and found it interesting in more than one way.

Thanks John