Impact of tomato black ring virus (TBRV) on quantitative and qualitative feature of Vitis vinifera L. Cv. Merlot and Cabernet franc

Abstract

Context and purpose of the study – Fifteen nepoviruses are able to induce fanleaf degeneration in grapes which is economically the most imprtant viral disease. Grapevine fanleaf virus (GFLV) is the main causal agent of this disease worldwide and Arabis mosaic virus (ArMV) is the second most important nepovirus involved in this disease in Europe. A third nepovirus has been described in France. Indeed, Tomato Black Ring Virus (TBRV) was detected in vines for the first time in France on a multi‐varietal plot in 2009. The objective of the study was to quantify the impact of TBRV on two varieties of this plot.

Material and methods – Quantitative and qualitative impact of TBRV assessment was carried out in 2010 and 2011. Over 200 vines were analyzed by ELISA tests in order to determine their virus status. Vines were distributed in four groups: 40 vines of Merlot TBRV positive versus 40 merlot vines virus free and 40 vines of Cabernet franc TBRV positive versus 40 free of the virus. For each vine, the presence of eleven other viruses was investigated. In 2010 and 2011 shoot length was measured. In 2010, grape composition was analyzed to determine technological maturity and phenolic maturity of each vine in relation with its virus status.

Results – Shoot length and total pruning weight is reduced in TBRV infected vines, while lateral number is increased. All yield parameters are affected by the presence of the virus. Vines affected by TBRV produce less bunches and berries and smaller berries compared to healthy vines. Yield loss is greater on Merlot compared to Cabernet franc. Grape quality parameters seem to be less affected by the presence of TBRV. These results provide essential elements for the management of the viral disease in the vineyard.