Macrowine 2021
IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Is it possible to approximate the technological and phenolic maturity of grapes by foliar application of elicitors?

Is it possible to approximate the technological and phenolic maturity of grapes by foliar application of elicitors?

Abstract

AIM: The increase in the temperature and the more severe water stress conditions, trends observed in recent years as a consequence of climate change, are leading a mismatch between the technological and phenolic maturity of grapes [1]. As a strategy to face this situation, the use of apatite (Ap) nanoparticles as nano-transporters of the elicitor, methyl jasmonate (Ap-MeJ), is proposed. Elicitors are compounds that, when applied to plants, activate their defense mechanisms, increasing the synthesis of secondary metabolites, mainly phenolic compounds [2, 3]. To date, methyl jasmonate (MeJ) has been used conventionally, but its “nano” application could improve its penetration into the plant, releasing it slowly, which would allow a reduction in the dose to be applied. Therefore, the objective of this work was to study the influence of foliar application of conventional MeJ and MeJ formulated in “nano” form on the composition of Tempranillo grapes during ripening.

METHODS: The experimental design was a randomized block design with three treatments, each in triplicate, with 10 vines per replicate. Foliar applications were carried out at veraison and 7 days later. In each application, 200 mL of solution was applied per plant, being the treatments: control (water), MeJ (10 mM) and Ap-MeJ (1 mM). Grape samples were taken at five points in time: one day before the first application (Fol1), one day before the second application (Fol2), fifteen days after the second application (Pre: pre-harvest), the day of harvest (Vend) and 15 days after harvest (Post: post-harvest). In each sample, the general parameters were determined using official methods [4]: ºBrix, pH, total acidity, glucose+fructose, malic acid, and total phenols.

RESULTS: The results obtained with the foliar application of MeJ as a tool to approximate the phenolic and technological maturity are promising. It has been observed that both, conventional MeJ and Ap-MeJ treatments, slightly reduced ºBrix of grapes and increased their phenolic content. Throughout ripening, the increase in phenolic compounds was mainly evident from pre-harvest to post-harvest, with a higher content in grapes treated with Ap-MeJ.

CONCLUSIONS:

The application of MeJ could be an appropriate technique to mitigate the negative effects of decoupling in grape ripening related to the climate change. Moreover, the use of Ap-MeJ allows to optimize its dosage, contributing to a sustainable and economically viable viticulture.

DOI:

Publication date: September 1, 2021

Issue: Macrowine 2021

Type: Article

Authors

Teresa Garde-Cerdán , Carretera De Burgos, Pérez-Álvarez, Baroja, Ramírez-Rodríguez,  Martínez-Vidaurre, Delgado-López P. Rubio-Bretón, Garde-Cerdán

Instituto De Ciencias De La Vid Y Del Vino (Csic, Universidad De La Rioja, Gobierno De La Rioja). Km. 6. 26007 Logroño, Spain,E.P.
Instituto De Ciencias De La Vid Y Del Vino E.
Instituto De Ciencias De La Vid Y Del Vino G.B. Universidad De Granada J.M.
Instituto De Ciencias De La Vid Y Del Vino J.M.
Instituto De Ciencias De La Vid Y Del Vino T.
Instituto De Ciencias De La Vid Y Del Vino

Contact the author

Keywords

Elicitors; nanotechnology; methyl jasmonate; foliar application; vineyard; grape composition; ripening; phenolic maturity; technological maturity; climate change

Citation

Related articles…

Is wine terroir a valid concept under a changing climate?

The OIV[i] defines terroir as a concept referring to an area in which collective knowledge of the interactions between the physical and biological environment (soil, topography, climate, landscape characteristics and biodiversity features) and vitivinicultural practices develops, providing distinctive wine characteristics. Those are perceptible in the taste of wine, which drives consumer preference and, therefore, wine’s value in the marketplace. Geographical indications (GI) are recognized regulatory constructs formalizing and protecting the nexus between wine taste and the terroir generating it. Despite considering updates, GIs do not consider the nexus as a dynamic one and do not anticipate change, namely of climate. Being climate a fundamental feature of terroir, it strongly impacts wine characteristics, such as taste. According to IPCC[ii], many widespread, rapid and unprecedented changes of climate occurred, some being irreversible over hundreds to thousands of years. Climatic shifts and atmospheric-driven extreme events have been widely reported worldwide. Recent climatic trends are projected to strengthen in upcoming decades, whereas extremes are expected to increase in frequency and intensity, forcing wines away from GI definitions. Geographical shifts of viticultural suitability are projected, often moving into regions and countries different from current ones. Some authors propose adaptation in viticulture, winemaking and product innovation. We show evidence of climate changing wine characteristics in the Douro valley, home of 270-year-old Port GI. We discuss herein resist or adapt stances for when climate changes the nexus between terroir and wine characteristics. Using the MED-GOLD[iii] dashboard, a tool allowing for easy visual navigation of past and future climates, we demonstrate how policymakers can identify future moments, throughout the 21st century under different emission scenarios, when GI specifications will likely need updates (e.g., boundaries, varieties) to reduce climate-change impacts.

Measurement of redox potential as a new analytical winegrowing tool

Excell laboratory has initiated the development of an analytical method based on electrochemistry to evaluate the ability of wines to undergo or resist to oxidative phenomena. Electrochemistry is a powerful tool to probe reactions involving electron transfers and offers possibility of real-time measurements. In that context, the laboratory has implemented electrochemical analysis to assess oxidation state of different wine matrices but also in order to evaluate oxidative or reduced character of leaf and soil. Initially, our laboratory focused on dosage of compounds involved in responses of plant stresses and we were also interested in microbiological activity of soils. These analyses were compared with the measurement of redox potential (Eh) and pH which are two fundamental variables involved in the modulation of plant metabolism. Indeed, the variation of redox states of the plant reflects its biological activity but also its capacity to absorb nutriments. The Eh-pH conditions mainly determine metabolic processes involved in soil and leaf and our goal is to determine if this combined analytical approach will be sufficiently precise to detect biological evolutions (plant health, parasitic attack…).

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

From a local to an international scale: sensory benchmarking of PDO wines. Quincy and Reuilly PDO wines (Sauvignon blanc) as a case study (France)

In a collective marketing strategy, the Protected Designation of Origin (PDO) can be used as a quality indicator. To highlight terroir specificities, it is useful to know how the wines are positioned on the local, national or international market from a sensory point of view. This is especially true for a comparison of varietal wines (e.g. Sauvignon blanc). We focus on the case of two closed Loire Valley PDO (France): Quincy and Reuilly. Three distinct tastings were organized. Firstly, at the local level comparing the 2 PDO (11 and 9 wines, 17 professional assessors); secondly at a regional level adding 3 closed PDO: Menetou-Salon, Sancerre and Pouilly-Fumé (3 wines per PDO, 16 assessors) and thirdly at an international level comparing these 5 PDO with Sauvignon Blanc wines coming from South Africa, New Zealand and Chile (1 to 3 wines per PDO, 19 assessors). All the wines were from the 2019 vintage and were considered to have a traditional elaboration process without contact with oak. A sensory descriptive analysis was performed using an aroma wheel allowing to combine a Check-All-That-Apply methodology, often used in sensory benchmarking, with a hierarchical structuration of the attributes. The aim is to facilitate data acquisition in a professional context without common training, to consider the hierarchical relationships among the attributes during the data analysis and to be able to characterize wines with a large range of sensorial variability. We use univariate, multivariate and clustering analyses. Similarities and differences between Quincy and Reuilly PDO wines and other Sauvignon blanc wines were identified. Specific attributes can distinguish the two PDO and different proximities exist with other local PDO, while clear differences were observed compared to international wines. Our study contributes to propose and discuss a method to do a wine sensory benchmarking highlighting sensory specificities linked to origin.

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…