Evaluation of mechanical properties of berries on resistant or tolerant varieties of grapevine

Abstract

An experimental site located in Trentino (North-Eastern Italy), characterized by considerable rainfall that normally requires several plant protection treatments, was used to assess the behavior of 15 grape varieties resistant to the main fungal diseases from an agronomic, quantitative, qualitative, nutritional, and physiological point of view, since 2015. At the 4th year of planting (2016), mechanical properties (berry firmness, berry skin hardness, and thickness) of berries were evaluated using a TAxT2i Texture Analyzer in order to get information about parameters useful for wine process. The varieties showed significant differences in the studied parameters. Regent had the highest values of berry firmness, whilst Johanniter and Cabino the lowest. Cabernet Cantor and Cabernet Cortis generally presented higher values of berry skin hardness than the other varieties. Conversely, the lowest values of skin hardness were recorded in Johanniter, followed by both Solaris and Cabino. Souvignier gris, Prior, and Bronner had significantly higher values of berry skin thickness than Cabino, which, in turn, did not differ from the levels found in Helios, Muscaris, Aromera, and Regent berries, with values above 175 µm, range largely found in grapevine cultivars normally grown. The association between mechanical properties of berries and qualitative data could be used as an aid in decision-making about wine processes.