Viticulture is facing emerging challenges not only because of the effect of climate change on yield and composition of grapes, but also of a social demand for environmental‐friendly agricultural management. Adaptation to these challenges is essential to guarantee the sustainability of viticulture. The aim of this review is to present adaptation possibilities from the soil‐hidden, and often disregarded, part of the grapevine, the roots. The complexity of soil–root interactions makes necessary a comprehensive approach taking into account physiology, pathology and genetics, in order to outline strategies to improve viticulture adaptation to current and future threats. Rootstocks are the link between soil and scion in grafted crops, and they have played an essential role in viticulture since the introduction of phylloxera into Europe at the end of the 19th century. This review outlines current and future challenges that are threatening the sustainability of the wine sector and the relevant role that rootstocks can play to face these threats. We describe how rootstocks along with soil management can be exploited as an essential tool to deal with the effects of climate change and of emerging soil‐borne pests and pathogens. Moreover, we discuss the possibilities and limitations of diverse genetic strategies for rootstock breeding.

Background and Aims: Net carbon gain commonly estimated from leaf photosynthesis measurements often overestimates grapevine production. This is usually attributed to canopy complexity and a lack of plant respiration data. The present study evaluates the significance of plant respiration in correcting this overestimation. Methods and Results: Non-grafted and non-productive young plants of four grapevine varieties were grown either under irrigation or controlled water stress for 30 days. Daily time courses of leaf photosynthesis and transpiration were determined along with measurements of leaf, stem and root respiration, from which whole plant carbon balance was estimated. Up to 30–60% of carbon obtained by photosynthesis is used in respiration, with root respiration being the largest user of fixed carbon (up to 75%). Conclusions: Whole plant respiration represents a significant part of total carbon balance and accounts for the largest part of the discrepancy between photosynthesis-based estimates of plant production and actual plant production. Significance of the Study: The present study presents a quantitative evaluation of the importance of plant respiration in grapevine carbon balance and biomass production, highlighting that gas exchange studies aiming predict plant production should include estimates of respiration, especially of roots.

There is currently a high requirement for field phenotyping methodologies/technologies to determine quantitative traits related to crop yield and plant stress responses under field conditions. We employed an unmanned aerial vehicle equipped with a thermal camera as a high-throughput phenotyping platform to obtain canopy level data of the vines under three irrigation treatments. High-resolution imagery (< 2.5 cm/pixel) was employed to estimate the canopy conductance (g c ) via the leaf energy balance model. In parallel, physiological stress measurements at leaf and stem level as well as leaf sampling for primary and secondary metabolome analysis were performed. Aerial g c correlated significantly with leaf stomatal conductance (g s ) and stem sap flow, benchmarking the quality of our remote sensing technique. Metabolome profiles were subsequently linked with g c and g s via partial least square modelling. By this approach malate and flavonols, which have previously been implicated to play a role in stomatal function under controlled greenhouse conditions within model species, were demonstrated to also be relevant in field conditions. We propose an integrative methodology combining metabolomics, organ-level physiology and UAV-based remote sensing of the whole canopy responses to water stress within a vineyard. Finally, we discuss the general utility of this integrative methodology for broad field phenotyping.

Severe water stress can lead to hydraulic disfunction, reducing plant conductance or even causing death. Some plants exhibit hydraulic vulnerability segmentation between organs to reduce this risk. However, its role in influencing drought tolerance and resistance in grafted plants, such as grapevine, remains unclear. This study evaluates the physiological responses, drought tolerance, hydraulic vulnerability segmentation, and xylem anatomy of 2-year-old Vitis vinifera cv. Tempranillo scion grafted onto two rootstocks: 110-Richter (110R) and Sélection Oppenheim 4 (SO4). After subjecting the plants to drought conditions until the onset of embolism in the leaf (water potential corresponding to 12% loss of xylem hydraulic conductivity, P12), we analysed the physiological consequences during recovery. Grapevine exhibits hydraulic vulnerability segmentation not only within scion organs but also between the scion and rootstock. Although no differences in scion drought tolerance and embolism resistance were observed between combinations, Tempranillo-110R exhibited higher leaf minimum conductance, leaf P12 values, and root biomass. In contrast, Tempranillo-SO4 displayed larger vessel diameter and higher hydraulic conductance. These differences may explain the slower recovery of Tempranillo-110R compared with Tempranillo-SO4, which showed higher stomatal and root-to-stem hydraulic conductance. These findings indicate that in selecting rootstock, consideration should be given to drought resilience alongside vigour and productivity, especially given the increasing occurrence of severe drought periods due to climate change.

Climate change threatens worldwide grapevine production, especially in Mediterranean areas. To assume this challenge, the replacement of plant material to choose one more adapted to the new environmental conditions has been proposed as one of the possible solutions. Thus, the study of genetic variability in water-use efficiency (WUE) is needed to guarantee the survival of viticulture in those critical areas. In this study, the variability of WUE in 23 Tempranillo clones growth in pots and submitted to well-watered conditions and moderate water stress was studied along two consecutive years. Leaf net photosynthesis (AN), stomatal conductance (g_s), and plant growth parameters were measured, in addition the instrisic WUE (AN/g_s), biomass production, and water consumed were calculated. Results show a clear genotype effect for most of the studied parameters, but, with an important year by year variability. We identified different clonal behavior in response to soil water availability, that permits to classify them as water-savers vs water-spenders. In general, there was no found relationship between leaf and plant WUE, even some genotypes as 232 or 1048 were coincident in higher leaf WUE showed highly productive in terms of biomass accumulation per unit of water applied.