S20 - Session O3 - Use of a portable vis / NIR device to monitor the accumulation of anthocyanins during ripening in berries of Sangiovese cv (Vitis vinifera L) under heat wave conditions

Authors: Gabriele Valentini *, Gianluca Allegro, Chiara Pastore, Riccardo Mazzoleni, Giovanni Fiori, Andrea Galletti, Ilaria Filippetti

The impetuous progress of precision techniques in viticulture and the goal of quickly establishing the optimal harvest time, have led to the development of increasingly efficient portable vis / NIR devices. These tools can reduce the sampling time and the costs of chemical analyses usually applied during ripening to monitor the composition of the berries and establish the right harvest time. Nowadays, evaluation of polyphenols and anthocyanins in red grapes is rarely performed, since it involves costly and time-consuming procedures. The literature has also highlighted that in recent years - characterized by strong heat waves - the accumulation of anthocyanins in grapes may be strongly penalized. In this context smart/easy techniques both to verify the evolution of anthocyanin concentrations and to reduce the negative impact of heat temperature on the grapes are strongly pursued objectives. Starting from these assumptions, in the two-year period 2019-2020, at the University of Bologna, a non-invasive and portable vis / NIR device (berry adapted DA-meter®) was evaluated to monitor the accumulation of anthocyanins in grapes subjected to kaolin treatment. In particular, two treatments were performed: untreated control (C) and kaolin (K) applications on cv. Sangiovese in order to verify the mineral cooling effects on berries and the consequent impact on anthocyanin accumulation. The mineral was sprayed twice around the veraison on the entire canopy at a 3% concentration. The results showed that the application of the kaolin was able to reduce the berry temperatures in both years of the trial as compared to the untreated control (C). Furthermore, the cooling effect determined an increase in anthocyanin on grapes detected by both chemical and non-destructive approaches. In conclusion the berry adapted DA-meter® appears to be an excellent and smart device for quick in-field measurements.