A field survey of grapevine germplasm susceptible to Eutypa dieback

Authors: TRAVADON, RENAUD - University Of California, Davis; Heinitz, Claire; Baumgartner, Kendra

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/27/2023
Publication Date: 2/12/2024
Citation: Travadon, R., Heinitz, C.C., Baumgartner, K. 2024. A field survey of grapevine germplasm susceptible to Eutypa dieback. HortScience. 59(3):362-370.
DOI: https://doi.org/10.21273/HORTSCI17521-23

Interpretive Summary: Eutypa dieback of grapevine is a trunk disease that impacts vineyard productivity worldwide. Cultivars vary in resistance, based primarily on results from controlled inoculations in the greenhouse. Such controlled inoculations to evaluate resistance are more reliable for re-creating wood symptoms, compared to leaf symptoms. An alternative approach for evaluating resistance based on leaf symptoms is to make observations in the field, under natural levels of inoculum. Leaf symptoms were rated in a field survey for 3 years, over the course of 5 years, of 1,200 accessions in a Vitis vinifera collection at the USDA National Clonal Germplasm Repository in Davis, California. Leaf symptoms were rated in early May of 2011, 2013, and 2015. Of the 1,200 wine and table-grape accessions we surveyed, leaf symptoms were present in at least one of three study years for 122 accessions. ‘Corbu blanc’, ‘Frankenthal blanc’, and ‘Pinot gris’ were the only accessions that had leaf symptoms in all three study years. We identified cultivars with a shared genetic background that also had severe symptoms, such as ‘Chasselas’ and ‘Muscat’. Field evaluations are eventually necessary to validate phenotyping assays, and preferably under diverse field conditions, as complex interactions among the pathogen, host, and the environment can sometimes cause resistant cultivars to show high levels of symptom severity, under disease-conducive conditions in the greenhouse.

Technical Abstract: Eutypa dieback of grapevine is a trunk disease that impacts vineyard productivity worldwide. Cultivars vary in resistance, based primarily on results from controlled inoculations in the greenhouse. Such controlled inoculations to evaluate resistance are more reliable for re-creating wood symptoms, compared to leaf symptoms. An alternative approach for evaluating resistance based on leaf symptoms is to make observations in the field, under natural levels of inoculum. Leaf symptoms were rated in a field survey for 3 years, over the course of 5 years, of 1,200 accessions in a Vitis vinifera collection at the USDA National Clonal Germplasm Repository in Davis, California. Leaf symptoms were rated in early May of 2011, 2013, and 2015. Of the 1,200 wine and table-grape accessions we surveyed, leaf symptoms were present in at least one of three study years for 122 accessions. ‘Corbu blanc’, ‘Frankenthal blanc’, and ‘Pinot gris’ were the only accessions that had leaf symptoms in all three study years. We identified cultivars with a shared genetic background that also had severe symptoms, such as ‘Chasselas’ and ‘Muscat’. Field evaluations are eventually necessary to validate phenotyping assays, and preferably under diverse field conditions, as complex interactions among the pathogen, host, and the environment can sometimes cause resistant cultivars to show high levels of symptom severity, under disease-conducive conditions in the greenhouse.