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POSTERS: Pathogenicity and host specificity

Norton grapevine resists grapevine vein clearing virus
Wenping Qiu - Missouri State University. Susan Howard- Missouri State University, Sylvia Petersen- Missouri State University

Norton is a North American hybrid grape with a major genetic background of Vitis aestivalis, which is native to the Midwest region of the United States. Norton has been known to be resistant to the fungal pathogens causing powdery mildew and downy mildew. Grapevine vein clearing virus (GVCV) is endemic to the same region and associated with a disease that causes vine decline and death of cultivated grapevines. In a project assessing grape cultivars’ resistance to GVCV by graft-transmission, we did not detect GVCV in grafted Norton either as a rootstock or a scion by PCR assays or Next Generation Sequencing. In a survey of a foundation vineyard over five years, we did not find GVCV infection in all 74 Norton vines, although susceptible grape cultivars in adjacent rows were infected. Additionally, Norton was not infected with GVCV by aphid-transmission in greenhouse experiments. These results demonstrate that Norton is resistant to GVCV, revealing a new trait. Genetic mechanisms of Norton’s resistance to a virus and assessment of its resistance to other grapevine viruses merit further investigation.