Effect of fungi addition, root preparation, and other factors on the success of vine replacement in an established vineyard

Studying heat stress response of grapevine berries in the field often relies on weather conditions during the growing season. We constructed a mobile heating device, able to induce controlled heat stress on grapes in vineyards. The heater consisted of six 150 W infrared lamps mounted in a profile frame. Heating power of the lamps could be controlled individually by a control unit consisting of a single board computer and six temperature sensors to reach a pre-set temperature. The heat energy applied to individual berries within a cluster decreases by the squared distance to the heat source, enabling the establishment of temperature profiles within individual clusters. These profiles can be measured by infrared thermography once a steady state has been reached. Radiant flux density received by a berry depending on the distance was calculated based on a view factor and measured lamp surface temperature and resulted to 665 Wm-2 at 7cm. Infrared thermography of the fruit surface was in good agreement with measurements conducted with a thermocouple inserted at epidermis level. In combination with infrared thermography, the presented device offers possibilities for a wide range of applications like phenotyping for heat tolerance in the field to proceed in the understanding of the complex response of plants to heat stress. Sunburn necrosis symptoms were artificially induced with the aid of the device for cv. Bacchus and cv. Sylvaner in the 2020 and 2021 growing season. Threshold temperatures for sunburn induction (LT5030min) were derived from temperature data of single berries and visual sunburn assessment, applying logistic regression. A comparison of threshold temperatures for the occurrence of sunburn necrosis confirmed the higher susceptibility of cv. Bacchus. The lower susceptibility of cv. Sylvaner did not seem to be related to its phenolic composition, rendering a thermoprotective role of berry phenolic compounds unlikely.

Valpolicella is a wine region characterized by a wide use of the technology of grape drying for the production of two red passito wines, recognized as PDOs, “Recioto della Valpolicella” and the most famous “Amarone della Valpolicella”. Geographical origin of the grapes can influence wine composition by grape chemical composition yeast behaviour during fermentation. This study investigates the impact of different commercial yeast strains on aroma profiles of wines produced with withered grapes of different origins. In addition, the influence of spontaneous fermentation is also considered. METHODS: Experimental red wines were produced with a standard winemaking protocol with withered Corvina and Corvinone grapes obtained from two different geographical areas within the Valpolicella region. Fermentations were carried out with four different commercial yeasts plus a spontaneous fermentation. Wines were analysed by means of SPE- and SPME-GC-MS techniques and sensory analysis (sorting task).

Recently, foliar treatments with mineral-based compounds have shown positive effects on grapevine production by protecting grape from thermal excesses and reducing the decoupling between technological and phenolic maturity caused by climate change. Unraveling the effect of mineral particle applications on grape-associated microbes is pivotal for successful wine processing, due to the influence of the microbiota on wine composition and stability. To our knowledge, this is the first work that comprehensively studied the effects of kaolin and chabasite-rich zeolitites treatments on grape-related microorganisms (by real-time PCR quantification of total fungi, Hanseniospora uvarum, Metschnikowia pulcherrima, plant-associated bacteria and lactic acid bacteria), the expression of genes related to the flavonoid biosynthesis (PAL1, CHS1, F3H2, DFR, LDOX, UFGT, MYBA1, GST4, FLS4 genes) and the berry composition (°Brix, pH, acidity and anthocyanin concentrations) in cv. Sangiovese during ripening in two growing seasons (2019 and 2020).

The aim of the present work was to investigate Sauternes wines aromas. The flavor profiles of two wines (vintages 2002 and 2003) were investigated. Key-odorants have been determined by AEDA applied to Amberlite XAD-2 resin extracts. Various complementary techniques were used to identify the compounds (pHMB extraction, chemical synthesis of non-commercial standards, co-injections on two capillary columns, odor description at the sniffing port, GC-MS and GC-PFPD).

Agriculture faces many global warming challenges especially in the Mediterranean region. Many strategies have been proposed in viticulture to manage global warming. Rootstocks are among them since they may affect water uptake and the scion’s performance.
The study conducted in La Rioja, Spain, aimed to investigate the impact of different rootstocks (1103P and 161-49C) on the performance of the Tempranillo grapevine scion over a three-day cycles under drought and extreme conditions, specifically during a heatwave in July 2022, with maximum air temperatures up to 40ºC and average daily temperatures of 29.1ºC.