From average to individual fruit, a paradigm shift for accurate analysis of water accumulation and primary metabolism in developing berries

The increased intensity and frequency of heatwaves, coupled with prolonged periods of drought, are a significant threat to viticulture worldwide. During these conditions the more exposed leaves can show visible symptoms of heat damage. We monitored the functionality of photosystem II (PSII) in the field to better understand the impact of heatwaves on canopy performance. A factorial experiment was established in summer 2023 using Shiraz grapevines in the Barossa valley of South Australia, involving water-stressed and well-watered vines.

Heatwave events, defined as 2 or more days reaching ≥ 38 °C, are an increasingly frequent phenomenon threatening grape production worldwide. Heat stress has been shown to have negative consequences on grapevine physiology, leading to increased evaporative demand and intensified water stress. Due to heatwaves overlapping with important stages of grapevine reproductive development, spanning from berry set to the ripening stage, severe heat can potentially compromise yield and grape quality. The physiological response of grapevine to heat stress suggests a potential use of irrigation to mitigate heatwaves, however there is limited information regarding the irrigation amounts and timings needed for this purpose. Following up on a pivotal trial conducted between 2019 and 2022, in this study irrigation treatments with varying intensity and timing of application were refined to determine their potential mitigation of heat-associated damage to yield and fruit composition.

The correlations between vine water deficit cumulated over the ripening period of grapes, assessed by ΔC13 in must sugar, and the main analytic variables of grapes are significant. As a result ΔC13 is a useful tool in zoning homogeneous areas according to their technological qualities when harvesting.

Oak wood selection and maturation are essential steps in the course of barrel fabrication. Given the existence of many factors involved in the choice of raw material and in natural seasoning of oak wood, it is very difficult to determine the real impact of seasoning and selection factors on oak wood composition. A sampling was done to study the evolution of oak wood chemical composition during four seasoning steps: non matured, 12 months, 18 months and 24 months. For this sampling, three selection factors were taken into account: age, grain type and the Polyphenolic Index measured by Oakscan®. Besides extractables
(~10%), three polymers constitute the main part of oak wood: cellulose, hemicelluloses and lignins.

The use of hybrids in viticulture is one of the alternatives for sustainable production in hot and rainy regions during grapevine maturation. This sustainable production concerns the reduction of pesticide use, adaptation to climate and control of vine decline. The SR 0.501-17 wine grape hybrid, developed in the grapevine program of the Agronomic Institute of Campinas (IAC), is characterized by producing white grapes with small spherical berries with seeds. The agronomic characterization of this hybrid, especially in different climatic conditions, as well as the evaluation of its performance in winemaking are necessary. The objective of this work was to characterize the duration and thermal requirements of the different phenological stages and the influence of rainfall on the physicochemical characteristics of the must in two contrasting climate regions of the State of São Paulo.