Hi Everyone!!
The PowerPoint presentations from last summers National Clean Plant Network-Roses meetings are now posted. Hopefully the pictures and outlines with bullet points of the talks will provide a pretty good idea of of the messages conveyed. The RRD material I think is especially valuable for us as rose breeders. There are some lists of roses that haven’t showed symptoms yet in the field trials in TN and DE (about 7% of the several hundred planted out haven’t shown symptoms yet). Such roses include many Ag Canada roses that have R. x kordesii or R. arkansana in them. Not all Ag Canada roses have been planted out yet, so these lists are far from exhaustive. If a rose is included on this list, it doesn’t mean it won’t or can’t get RRD, but that just to date it looks good. These roses may just be harder to infect or may not show symptoms as prominently. There was some great work done by a graduate student (Maddie) following adjacent roses to infected plants showing symptoms that were rogued in CA production fields to see how many plants outward eventually test positive. She tested 5 plants out from each side and, unfortunately, in some cases most all the plants eventually showed symptoms. From my understanding, she grew them in the greenhouse free from eriophyid mites, so the infections that arose are ones that were there when she got the plants.
Here is the link to all the talks:
https://ucanr.edu/sites/ncpnrose/Network_Business/may_2017_agenda/2018_Meetings/
Thank you Dave. I was particularly interested that Rose Spring Dwarf (RsDAV) was found in 21 of the 150 plants tested in the Florida roses. Was this point discussed?
For completeness: Blackberry chlorotic ringspot virus (BcRV) was found in one plant, Prunus necrotic ringspot virus (PNRSV) was found in 6 plants, and Rose yellow vein virus (RYVV) was found in six plants. Four plants had mixed viruses - two had RsDAV and RYVV (Paul Neyron and Pulich Children) and two had PNRSV and RsDAV (B. rugosa ruba and Red Pinocchio).
In my last post I specifically asked Dave concerning any discussion of the testing of the Florida roses. Of course if anyone else was at the meeting, please feel free to add your knowledge concerning my request.
I did find the following in the NCPNR Annual Teleconference Minutes, Monday, December 11th, 2017:
“In the 1980s and 90s, Malcolm Manners established a virus tested collection of Old Garden Roses, NCPN is beginning to aid him by assessing the virus status of his collection.”
Hi Henry, at the meeting the presentations helped to update the group on the progress being made in various projects and efforts related to roses and clean stock. There was discussion along the way after each talk with a short time for Q&A and then plenty of time over meals and breaks for people to specifically visit with presenters. A key goal throughout the meetings was to place the growing understanding of information and efforts into context to help guide and set future priorities to try to pursue fundable efforts through the NCPN and develop proposals. It is a bit different than a standard scientific meeting in how things are organized and run. Specifics beyond the data shared about Rose Spring Dwarf virus was not discussed from my memory.
This past year rose rosette virus (causing RRD) was a key virus focus, especially the second day. There is much that could be shared from the people involved in the RRD research funded by the Specialty Crop Research Initiative grant. The goal of the NCPN funding and effort is to help take current tools available from the research that is being done by others and transfer it for practical application to better the industry and consumers with clean stock. Under this umbrella such fundable things include optimizing diagnostics tools for detecting characterized viruses that are reliable in detection and can be used by the wide network of plant disease clinics. Another area of fundable activity includes especially cleaning up and making available clean stock that has been indexed for the viruses we know are especially problematic and to make that clean stock available to propagators. The NCPN money isn’t meant to do fundamental virus characterization of new viruses (how they are spread, their sequence, what percentage of public gardens have some infected plants and with what viruses, etc.) per say. The goal or focus is to use/optimize current tools to share with clinics to reliably test for key viruses and use those tools to test and get roses clean for those viruses into clean collections to make available to industry. The collection is periodically retested to make sure they are remaining clean.
Screening Malcolm’s great collection of primarily old garden roses for key viruses is a very good way to build upon the great work he has done and get the clean stock he currently has confirmed as clean and propagated and included in clean stock collections. Old Garden Roses are valuable, but unfortunately account for a more limited number of sales of roses in the marketplace compared to the key currently popular and mass propagated modern varieties. There are many OGRs as well, so it would be a huge effort to get a lot of them through the process and into the clean collection. It takes a lot of effort to get roses through the testing process with the standard molecular testing for viruses, also biological assays (grafting on ‘Burr’ multiflora and cherry), and then therapy for key varieties that prove to be dirty that we find very valuable to do this for and include. Partnering with Malcolm with his collection (many of which he put through heat treatment, not all from my understanding) can hopefully efficiently bring a good number of OGR’s into a clean collection relatively smoothly.
Thank you Dave. I hope that Rose Spring Dwarf Virus will get adequate attention from this program. It was not even mentioned in a very recent ARS e-book.
It appears that the British are joining us in the Rose Rosette fight.