Effect of hot‐water treatment on grapevine viability, yield components and composition of must

BACKGROUND AND AIMS: Hot‐water treatment (HWT) has been shown to be effective for the control of several endogenous and exogenous grapevine pests and diseases in dormant grapevine cuttings and young rooted vines. Little is still known, however, about the long‐term effect of HWT on plant viability under field conditions. The effect of HWT on the performance of dormant plants in a four‐growing seasons study was investigated. METHODS AND RESULTS: The effect of HWT at 53°C for 30 min on shoot mass, yield parameters and composition of must in dormant grafted plants (Tempranillo cultivar grafted onto 110 Richter rootstock) was evaluated. Eight bundles of 20 grafted plants were assigned to HWT, and eight additional bundles of 20 untreated grafted plants were prepared as a control (non‐HWT). Dormant grafted plants were immediately planted in two field sites in April 2007. Shoot fresh mass was evaluated during winter in four consecutive growing seasons. Yield parameters and must composition were evaluated in the third and fourth growing seasons. In general, there was no significant difference in shoot mass at pruning, yield parameters and must components between treatments, with the exception of the must total soluble solids and volumetric mass in the fourth growing season. CONCLUSIONS: The findings obtained in this study indicate that HWT at 53°C for 30 min did not affect plant viability, yield parameters and the main components of must composition, and could be successfully used commercially. SIGNIFICANCE OF THE STUDY: This study represents the first approach to investigate the long‐term effect of HWT on plant development, yield and composition of must under field conditions. It suggests that the success of HWT depends not only on the most adequate protocol applied by nurseries, but also on management practices before, during and after the propagation process that could affect the viability of HWT grapevine propagating material.