Direct and indirect effects of three virus infections on yield and berry composition in grapevine (Vitis vinifera L.) cv. 'Tempranillo'

•Viral diseases result in reduced vineyard performance.•GFLV had the most deleterious effects, followed by GLRaV-3.•GFLV increased soluble solids and colour is partly a direct effect.•GLRaV-3 negative effect on colour is not caused by delayed ripening.•GLRaV-3 higher pH is associated to imbalanced ripening.

Background and aimsViral diseases in grapevines result in reduced vineyard performance, but it remains unclear to which extent some of their effects are direct or indirect, or if both kinds of effects co-occur. The aim of this work is to evaluate the effect of three virus diseases (GFLV, GLRaV and GFkV) on cv. Tempranillo.Methods and resultsA wide dataset that comprised yield components and grape composition of 531 cv. Tempranillo accessions for seven years was used, comparing their performance depending on the presence of each virus. GFLV showed the highest deleterious effects, followed by GLRaV-3, whereas GFkV had no effect. GLRaV-3 and, especially, GFLV effects were very relevant.ConclusionsRegression analyses demonstrated that GFLV increases soluble solids (TSS) and colour density (CD) independently of yield reduction or advanced ripening, and causes higher pH independently of TSS. Similarly, GLRaV-3 detrimental effect on CD is not caused only by delayed ripening, and higher pH is associated to imbalanced ripening.Significance of the studyOur results highlight that a detailed analysis of a wide agronomic dataset allows a better understanding of virus diseases, unveiling to which extent some of their effects are direct or indirect.