A group at the University of East London used oryzalin to double the chromosomes of diploid and triploid roses. They found that “Significant increases in pollen viability accompanied chromosome doubling of all four diploids and one of the two triploids.”
Link: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12955205&dopt=Abstract
What a great article. I think that they got better pollen viability because TB and the other roses they used Martin Frobisher and that triploid are of complex genetic background. Although TB and MF are fertile as diploids, as tetraploids they seem to be acting a bit like amphidiploids or sometimes called allotetraploids. The chromosomes may be preferentially pairing with their copy allowing for more uniform pairing.
In my chromosome doubled polyanthas, which would be classed more as autotetraploids, I have found less fertility in the doubled version. In an upcoming Euphytica volume my article on this work and using trifluralin to double germinating seedlings will be printed. I cited that Kermani et al. paper quite a bit throughout my manuscript. I especially found it interesting that depending on the particular rose the doubled version behaved differently than the diploid for a number of traits. There wasn’t a clear trend in response to doubling for some traits.
Thanks Jim for posting the abstract to this great paper.
Sincerely,
David
Another point of interest to me was that it is stated in the Acknowledgements that this research was done with financial support of David Austin Roses Ltd.
On page 1200 of the paper the following appears:
“These tetraploids have been sucessfully used as pollen parents by David Autin Roses Ltd. (personal communication), who raised 1,998 seedlings using pollen of the tetraploid ‘Mermaid’ and 20 seedlings using pollen of the tetraploid ‘Pink Surprise’.”
The other roses mentioned were Therese Bugnet, Martin Frobisher, Alister Stella Gray X Abraham Darby, and New Dawn. I for one will be watching carefully the new roses that he introduces as it appears that he may have some “interesting very unique” roses in the pipeline.
A couple summers ago Michael Marriott came to MN and gave a presentation on the Austin roses. He is the nursery manager for David Austin’s nursery. I asked him how the breeding lines from these doubled versions of ‘Therese Bugnet’ and ‘Martin Frobisher’ are coming. He said that the lines are coming along, but nothing is ready to be introduced yet. That year ‘The Mayflower’ came out and I was just wondering if it was a descendant from this work, but it is not.
Hopefully the TB and MF tetraploids will transmit their winter hardiness. Many of the Austin roses are marginal or crown hardy here in zone 4 and it would be nice to have some more reliable landscape shrubs from him to use in this climate.
Sincerely,
David
In the February 2005 issue of the American Rose, pages 37-38, there are a number of new Austin rose registrations listed. Some of them have one parent listed like" unnamed seedling (light pink species type)".
I wonder if the parents of this type are the doubled chromosome roses that were mentioned above in this thread.
This is intresting-- I wonder if David Austin has plans to release the parentage of The Mayflower.
I have a well armed seedling of Abraham Darby that has some rugosa in it… Perhaps it will be intresting to breed it with The Mayflower.
My plans was to self this seedling, and also to try to breed this with The Pilgrim (it lacks pollen, and never sets hips). But the The Pilgrim is the most disease resistant Austin I have for the moment…