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Poster: Diseases of Plants: New & Emerging Diseases


Is there resistance to Rose Rosette Disease among cultivated roses?
K. ONG (1), J. Olson (2), T. Evans (3), M. Windham (4), E. Roundey (5), J. Lau (5), D. Byrne (5) (1) Texas A&M AgriLife Extension Service, U.S.A.; (2) Oklahoma State University, U.S.A.; (3) Department of Plant and Soil Sciences, University of Delaware, U.

Rose Rosette Disease (RRD) is caused by the Rose Rosette Virus (RRV) and transmitted by a wind-blown, eriophyid mite (Phyllocoptes fructiphilus). Little is known about resistance of roses to the virus or the mite vector. A few rose species, such as Rosa palustris, R. setigera, R. carolina, R. virginiana, and R. spinosissima have been reported to be resistant to RRD, but resistance in cultivated roses is unknown. Although it is possible to genetically introgress disease resistance from a wild species into the cultivated rose, the development of commercial roses would be quicker if there was a good source of resistance within the cultivated germplasm. Preliminary observational data on over 400 rose accessions indicates that there is resistance to RRD among the cultivated rose germplasm. Large field trials to assess RRD resistance of about 300 rose accessions have been planted in Tennessee and Delaware. The disease pressure in these trials is being augmented by inter-planting RRD infected roses among and by placing mite infested shoot tips from infected plants onto the plants to be tested for their resistance. In addition, smaller trials are being planted in Oklahoma and Texas to assess the level of RRD resistance of selected roses. Since disease symptoms may not appear for many weeks to months after inoculation with the virus, we anticipate this will be a long term study and it may be 1 or more years before we know if resistance occurs in cultivated roses.