Rose Rosette News

If you are using or were planning on using Top Gun in your hybridizing program to get rose rosette virus resistance, you may find this thread of interest:
http://forums.gardenweb.com/discussions/4907117/rose-rosette-disease?n=11

So what does this mean? That no commercial cultivar is safe?

So far, that appears to be the case…

That’s troubling :confused: often a small percentage are resistant to these sort of things.

I haven’t heard people say a whole lot about rugosas, but from what I’m hearing from folks in RRD infected areas straight rugosas are actually resistant. Is that true? Have people found symptomatic rugosas? For standard commercial cultivars, a challenge is that infection can take a while to show up, especially without graft innoculation an relying on natural infection, so we may get excited early on that something is resistant, but then goes down later. Longer term trials coupled with graft innoculation of the ones showing promise using natural infection hopefully will lead to finding some resistance in the standard gene pool we’d be confident about and that would be repeatable over sites and by different researchers and infection method variations.

I used your link Henry and did some reading of messages that were posted and was very disapointed to read the following:

Jeri, I think what may save your roses is the wind directions off of the Pacific. I know wind directions have done serious damage to my roses this past year. (And my collection of H setigera hybrids are gone from RRD.)

I’d read that setigera was resistant.

It would be great to know what R. setigera hybrids went down. We don’t know how resistance (if truly present) is inherited. Maybe the number of generations for the hybrid cultivars are too far from the species and any resistance has segregated away or been diluted too much. Maybe resistance is recessive?? I’ve been wondering how resistant ‘Chuckles’ is. It sounds like from people that have a lot of RRD it can get it, but isn’t one of the first. My Oso Happy Smoothie has R. setigera as a great grandmother and goes down from what I learned, but it may just be too many generations away and didn’t inherit the critical genes. I don’t think we should give up on R. setigera yet as a source of resistance. It sounds like in areas where there is a lot of R. multiflora going down and R. setigera native people haven’t found infected R. setigera yet. Hopefully there is legitimate resistance in R. setigera and we’d learn its mode of action and how to better select for resistance in hybrids.

David, I picked up Smoothie in hopes that there might have some resitance genes there. Maybe it would be good to cross it back with something closer to setigera?

Hi Rob,

That sounds like a good plan. I wish there were more R. setigera hybrids/lines out there that are reblooming to work with. With a recent move and limited space for years before that I’ve struggled raising out too many one time blooming hybrids to move forward with. With a new place now with a couple acres and getting gardens started, I hope to raise out more one time bloomers as stepping stones to move forward. I’m grateful I haven’t had RRD in MN in my roses, but it is in the region. Hopefully a point will come to work with friends with more RRD pressure to share hybrids and see what holds up.

I’d also be interested to know how native populations of R. carolina and R. virginiana are faring if they are in RRD areas.

As would I Joe. I’m hoping there’s resistance with those two.

I wouldn’t dare conclude that the entirety of a species is resistant until a genetically diverse group of a large number of plants all display resistance. Resistant individuals aren’t evidence of species-wide resistance.

I have a Port Orford Cedar in front of the house that is ancient and continues to thrive long after all other individuals on our property were killed by Phytophthora lateralis many years ago. There were at least a dozen other Port Orford Cedars within 100 yards of this surviving specimen - many were as little as 40 feet away. All of the Cedars became visibly sick and died within a three year span and were dead within 18 months of showing signs of the disease. And yet this one tree remains, still healthy more than 10 years after all other plants of the species were killed. Local Ag Agency people have showed interest in our plant and it has been suggested we may have a resistant individual. But it would be a mistake if someone were to come to our farm now and see this surviving specimen and conclude that Port Orford Cedars are resistant to Phytophthora lateralis.

Good point Paul!!

It sounds like people have observed some R. palustris and R. virginiana individuals that have become infected. For R. setigera, it doesn’t sound like people have come across infected individuals even in regions where the species is sympatric with infected R. multiflora. Hopefully most R. setigera’s will prove to be resistant in the replicated trials going on and we’ll have a better understanding of what makes those genotypes resistant to be able to be strategic in how to best breed the resistance into cultivated roses.

Have there been reported cases of infection of rugosa, nitida or cinnamomea?

I think that there have been reports of rugosa infection, but rugosa are very sensitive to many foreign chemicals. I would have to hear that they failed the molecular test to be convinced.

Thank you, Henry. Not that I’m a scientific survey but I’ve yet to see an infection on a rugosa species. It would be nice if there is resistance in that species along with some other species as well.

I’d be interested if anyone has any information regarding potential resistance in nitida and cinnamomea.

Scientists seek public assistance in tackling rose rosette disease:

"[Kevin] Ong said his role on the project is also to educate the public about the disease, which will help monitor its location, so his team created a website, http://roserosette.org, as a clearinghouse for information.

‘The website also is a portal so that people can take pictures and submit them into the database. A verifier on the team looks at the photo to determine whether the plant depicted has rose rosette,’ Ong said."