Partial rootzone drying (PRD): strategic irrigation management as viticultural tool affecting plant physiology and berry quality

This study focuses on investigating the effects of climate change on the plant physiology and berries of Vitis vinifera cv “Monastrell” in a commercial vineyard managed organically in Southeastern Spain (Jumilla, Murcia). For this purpose, open top chambers and rainout shelters were employed to simulate warming (~2-7 ºC, W) and rainfall reduction (~30%, RR) respectively. Additionally, a combination of both treatments (W+RR) was employed. Vines without either top chambers or rainout shelters were considered as control (C). The experiment was established in February of 2023. Predawn leaf water potential (measured using a pressure chamber), stomatal conductance (assessed with a porometer at mid-morning) and leaf chlorophyll and flavonoid content (measured using the Dualex® leaf clip sensor) were analyzed at veraison (5 months after the installation of structures).

Context and purpose of the study. The genetic improvement of grapevines at the Edmund Mach Foundation (FEM) has evolved significantly since its inception, and its philosophy on sustainable viticulture through crossbreeding techniques aligns with the urgent need to reduce chemical use in agriculture.

Micro(mi)RNAs are small non-coding RNAs that regulate several pathways and are widely recognised as key players in plant development, tissue differentiation, and many other important physiological processes, including plant adaptation to biotic and abiotic stresses. The release of plant genomes and the application of high throughput sequencing have considerably extended miRNA discovery across many species, including grapevine (Vitis spp.). Despite their relevance in plant development, functional studies in grapevine to clarify the function of miRNAs are not yet available. Through the grapevine genetic improvement platform IMPROVIT at CNR-IPSP (http://www.ipsp.cnr.it/en/thematics/turin-headquarter-thematics/improvit/), we developed integrated approaches to discover miRNA function in grapevine.

Grapevine berries produce thousands of secondary metabolites of diverse chemical nature that have been largely detailed in the past due to their importance for defining wine quality. The wide Vitis vinifera diversity, resulting in thousands of different varieties well detailed in many studies regarding berries, is still not investigated in vegetative organs, leaves in particular. Deepening knowledge related to this aspect could be of great interest for many reasons (for example the possibility of using leaf extract for pharmaceutical, cosmetic and nutrition purposes) but, above all, for understanding the susceptibility of different grapevine varieties to pathogens.

This experiment tries to characterize the role of soil, climate and harvest date on the composition of grape-derivated thiols, 3-mercapto-hexanol (3MH) and 3-mercapto-hexile acetate (A3MH), in the white wines from Colombard varieties in Gascony (South-West of France). A network of 6 plots has been observed since 1999 on different pedologic units. The plots have common agronomical characteristics, plantation spacing (2,900 to 3,500 vines per ha), plantation aging (1985-1990), strength conferred by rootstock (SO4, RSB), soil management (grass covered 1 by 2) and training system (vertical shoot positionning pruned in single Guyot). Meteorological stations are located near the plots.