Beneficial Effect of Selective Virus Elimination on the Performance of Vitis vinifera cv. Chardonnay

Abstract

The effect of selective virus elimination on vigor, yield, and fruit quality of Vitis vinifera cv. Chardonnay was evaluated over six years in a replicate field trial. Test material was propagated from three clones infected by multiple virus combinations (GLRaV-1, GVB, and GRSPaV; GFkV, GLRaV-1, GVB, and GRSPaV; GLRaV-2, GLRaV-3, and GRSPaV) and virus-like diseases (vein mosaic and vein necrosis), and selected progeny were obtained after virus elimination by heat therapy and in vitro apex grafting. Some but not all viruses were eradicated in the progeny subjected to virus elimination, as shown by graft indexing and DAS-ELISA using appropriate γ-globulins, allowing for comparative viticultural performance analysis of clonal material with distinct viral infectious status. Elimination of GLRaV-2 had the highest beneficial impact with a marked increase in cumulative weight growth (21%), fresh fruit yield (22%), and sugar concentration of fruit juice (9%). Selective elimination of GLRaV-1, GLRaV-3, and GVB had also a beneficial impact, with an increase in vigor (0, 6, and 35%, respectively) and production (12, 3, and 16%, respectively), while fruit maturity indices were variably affected (0, 3, and 0% increase in fruit juice sugar and 13, 0, and 0% reduction in titratable acidity, respectively). These results offer new insights into the impact of GLRaV-2 on vigor, yield, and fruit quality of V. vinifera and provide strong evidence for the need to include detection assays for this detrimental virus in certification programs.