For those of you in the upper midwest, the American Rose Society has scheduled the following on Thursday, June 28, 2007 at 7 to 8 p.m.:
“Polyantha Rose Breeding”
by Kathy Zuzek and David Zlesak
There will also be a talk on Friday about rose viruses by Professor Ben Lockhart from the University of Minnesota.
Wow, they have the schedule on-line! Thanks Henry. I’m really excited for this meeting. Ben is fantastic. Much of his recent work is not on his bio on-line. It’s neat to see a younger picture of him too. He is a great guy who has a passion for what he does and has been interested in roses for a couple years now after discovering up to 5 viruses not reported in roses before! It makes me nervous knowing this. Some of these viruses are in new shrub roses that are propagated own-root and may never have been grafted before. Some of these viruses may be insect or soil transmitted (one shares characteristics of a soil transmitted virus which is a problem in lettuce production).
This past summer Ben presented the first of the rose virus work. A couple years ago he got a call from Jodi Fetzer at the New York Botanical Garden about strange symptoms in some of the roses. She sent samples and cuttings to Ben. The rose especially showing symptoms was ‘Ballerina’. It’s leaves would yellow and fall early in the season and there would be dark lines and symptoms on the stems. Since there was just general yellowing of one leaflet at a time and they would fall and do so early in the season it is easy to confuse with some nutrient or physiological problem. He confirmed the symptoms were associated with a virus by looking at it morphologically under the electron microscope and later he further characterized it by getting DNA sequence from it.
I helped him with some of the transmission work. We got some clean ‘Ballerina’ plants. He tried aphid transmission in the greenhouse and that didn’t do it. He found what appeared to be the same virus in hybrid teas at the MN Landscape Arboretum. I helped him graft an infected hybrid tea as well as infected ‘Ballerina’ onto clean stock. Surprisingly in only a month dramatic symptoms began to appear on the once clean material! He confirmed the virus’ presence in the plants showing transmission and the symptoms were associated with this virus. What is a really interesting link to this story is that the symptoms match that of Rose Streak Disease studied by Gary Secor in the late 1970’s. Gary is a potato pathologist now at North Dakota State. It appears that the causal agent of rose streak can now be associated with a pathogen (this virus). It was documented as being wide spread by Gary in rose production in the late 1970’s. Gary’s advisor was more of a field pathologist and maybe that’s why the detailed lab work was not pursued to find out that it is linked to a virus. Anyway, this virus appears to be widespread (New York Botanical Garden, MN Landscape Arb…). One of the challenges Ben had was to find a rose that only had this one virus to isolate it and see its effect alone when it is transmitted to clean stock. So many infected roses have more than one virus! Only one hybrid tea from the MN Lands. Arb. had only this one virus and that was the key to get it alone into ‘Ballerina’ and other roses. I helped him graft more clean ‘Ballerina’ roses lately so he can collect diseased leaves in order to generate antibodies so ELISA tests can be made. It’s been fun to see and be a little part of the process of characterizing a new virus.
The other viruses have a lot more work ahead for them. Ben has lots of projects going and likes to focus on and make progress in one thing at a time. His wish now is that hopefully with this knowledge and a antibodies to this one virus he can convince industry or other granting resources to fund some of this work so he can hire some help and make more progress.
I am excited for the opportunity to talk about polyantha breeding. My heart breaks thinking about Kathy and the rose breeding program at the U of MN. Due to general budget cutbacks in the department her job and the rose breeding program has been eliminated. This decision was made just a couple months ago. She is working into next month to close the program down. The seeds and current seedlings will be raised and sorted through in the next couple years and hopefully the core germplasm can be maintained. She started the program in ~1990 and has some polyantha roses scheduled for release next year and several good shrub roses in testing. She has developed a fantastic germplasm collection of parent stock tracing back mainly to Buck, Explorer and Species roses. Some are multiple generations from the species. I hope Kathy will still be able to be part of this talk at the convention. It will depend on where she will be working and living at that time. On Sunday of the convention the hybridizers will be at the Horticulture Research Center where we can see the roses of her breeding program. Hopefully Kathy will be able to join us then as well. The goal is to also bring some stock plants in of the polyanthas to be released to force this winter and root cuttings and see if young plants can be given away at the convention that people can easily take home to help promote them.
Vance Whitaker will probably be speaking at some point on his work characterizing black spot resistance in roses and diversity within the pathogen.