GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 Statewide relationships between water potentials, gas exchange and δ13c of grape musts in California. Implications for use in precision viticulture

Statewide relationships between water potentials, gas exchange and δ13c of grape musts in California. Implications for use in precision viticulture

Abstract

Context and purpose of the study– The measurement of carbon isotopic discrimination of musts (δ13C) at harvest is an integrated assessment of water status during ripening of grapevine. It is an alternative to traditional measurements of water status in the field, which is crucial for understanding spatial variability of plant physiology at the vineyard scale, proven useful for delineation of management zones in precision viticulture. The aim of this work was to attune the method for the first time to California conditions across a range of areas and cultivars with different hydric behavior, and to evaluate its efficiency in delineating management zones for selective harvest in commercial vineyards.
Material and methods – The experiment was performed in 91 experimental units located at four different locations across the State, planted to three different table and wine grape cultivars (Crimson Seedless, Cabernet Sauvignon, Merlot) whose hydric behavior ranged from isohydric to anisohydric, and in between. Leaf gas-exchanges and stem water potentials (Ψ) were measured routinely in each experimental unit, and the δ13C at harvest. At one of the locations, δ13C and water potentials were measured on an equi-distant grid, spatialized and clustered to compare their efficiency in the differentiated the vineyard block into two distinct zones having grapes with different flavonoid composition.
Results – A significant and direct relationship was evident between δ13C and average stem water potential (R2 = 0.72), stomatal conductance (R2 = 0.66) and net carbon assimilation (R2 = 0.62) measured throughout the season. Differences between the cultivars were small, independently from their reported hydric behavior and it was possible to pool all of them together. This was also true in crossed relationships between stem water potential, stomatal conductance, and net carbon assimilation that were not able to clearly discriminate between the reported hydric behaviors. A unique state-wide calibration was therefore developed between δ13C and plant water status. Simulation exercise demonstrated that variability in slope and R2 of the δ13C ~ Ψ regression can be caused by comparison of discrete measurements (Ψ) of water status to a continuous measurement (δ13C), and that apparent variability decreased with increasing sampling points of the discrete measurement (Ψ).The use of δ13C was then tested in a precision viticulture context. The management zones obtained by δ13C and stem water potentials were similar at 72% and allowed to separate the harvest in two pools, having statistically different grape composition (soluble solids, organic acids and anthocyanin profiles). Our results provided evidence that δ13C discrimination was a reliable and repeatable assessor of plant water status in vineyard ecosystems useful for delineation of management zones in precision viticulture.

DOI:

Publication date: September 18, 2023

Issue: GIESCO 2019

Type: Poster

Authors

Luca BRILLANTE1*, Runze YU2, Johann MARTINEZ-LUSCHER2, S. Kaan KURTURAL2

1 Dep. of Viticulture and Enology, California State University, Fresno, CA 93740. USA

2 Department of Viticulture and Enology, University of California, Davis, CA 95616, USA

Keywords

grapevine, δ13C, carbon stable isotopes, water status, leaf gas-exchange, precision agriculture, selective harvest

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Soil fertility and confered vigour by rootstocks

The adaptation of rootstock to scion variety and soil determines largely the control of the vegetative growth for grapevine. Many experiments were performed in the vineyard to classify the rootstocks according to their soil adaptation and to their effect on vine vigour. So far there are no data describing the course of appearance of rootstock effects after plantation. Moreover the underlying mechanisms of conferred vigour remain largely unknown.

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

Dead or dying vines must be replaced regularly in order to ensure the sustainability of a vineyard. Successful plant replacement is crucial to maintain yield and quality by encouraging balanced root and leaf development in vines. However, young vines planted within an established vineyard encounter several problems, ranging from poor soil conditions to competition with older vines with well-established root systems.  

Application of treatments to delay the ripening of grape varieties cultivated in valpolicella

Winegrape cultivars are particularly sensitive to temperature and recent changes in climate have advanced the onset of berry ripening, resulting in unbalanced fruit composition at harvest.

Terroir effects on the response of Tempranillo grapevines to irrigation in four locations of Spain: agronomic performance and water relations

We report the effects of different drip irrigation treatments on the agronomic performance and water relations of Tempranillo grapevines, pruned to a bilateral cordon

Study of the impact of nitrogen additions and isothermal temperature on aroma production in oenological fermentation

Nitrogen and temperature are two important factors that influence wine fermentation and volatile compounds production. Among the different compounds present in the must, nitrogen is an essential nutrient for the management of the fermentation kinetics but it also plays an important role in the synthesis of fermentative aromas. To address the problems related to nitrogen deficiencies, nitrogen additions during alcoholic fermentation have been developed.