Grapevine Performance Research Articles

Impact of steep slope management system and row orientation on canopy microclimate. Comparing terraces to downslope vineyards

Historically and under cooler climate conditions, steep slope vineyards yielded best quality wines and highest reputation, due to their distinctive microclimate, especially during ripening period. Nevertheless, steep slope vineyard sites primarily suffer from reduced competitiveness leading to abandonment, thus a loss of valuable vineyard sites. The aim of this work was to investigate differences in microclimatic conditions between different steep slope vineyard management systems and row orientations. Records of inner canopy microclimatic parameters were taken over two consecutive vegetation periods including seven vineyard pairs. A Bayesian mixed effect model was used to properly account for the complexity of the conducted experiment. Additionally, irradiation and canopy surface temperature data was compared. Grapevines planted downslope (control) exhibited a more even light distribution on canopy sides. Contrarily, at terraced vineyard sites canopy sides showed big differences regarding light interception, also affecting diurnal canopy surface temperature. Differences in N-S/E-W row orientation comparison were more pronounced compared to vineyard pairs aligned NE-SW/NW-SE. Night temperatures were slightly higher in terraced vineyards, while daily mean and maximum temperature and temperature amplitude were higher in vineyard rows planted in line of the greatest slope. While a treatment effect was not always clearly visible, an impact of row orientation on temperature microclimate was observed. Differences between treatments may become more pronounced under projected climate change conditions with consequences on physiological processes, thus grapevine performance influencing berry composition.

Detrimental effects of copper and EDTA co-application on grapevine root growth and nutrient balance

Continuous application of Cu-based fungicides and molluscicides may lead to Cu accumulation in vineyard soils. Grapevine (Vitis vinifera L.) inoculation with arbuscular mycorrhizal fungi (AMF) can be a suitable strategy to increase plant tolerance to the excessive levels of this element in the soil. However, the simultaneous use of EDTA-based fertilizers or phytosanitary products in those vineyards can affect metal mobility in the soil, with potential negative consequences for plants. Therefore, this study aimed to elucidate the effect of AMF inoculation on grapevine performance in Cu contaminated soils, in the presence or absence of EDTA chelates.Two-year-old plants growing in pots filled with an Arenosol, previously inoculated or not with two different AMF, were subjected to three soil treatments: control, Cu addition; Cu and FeNaEDTA addition. Four months later, at the end of the growing season, plant vegetative growth parameters, root colonization as well as soil, root and leaf nutrient contents were analyzed.In the soil where Cu was applied, Rhizoglomus irregulare- and Funneliformis mosseae-inoculated plants showed significantly higher root biomass than the non-inoculated ones, and R. irregulare-inoculated plants were the ones with the highest root P and Fe concentrations. However, when Cu and FeNaEDTA were applied together to the soil, AMF inoculation was no longer an asset for grapevines, and overall, root biomass decreased, translocation of Cu to leaves was stimulated, and a significant decrease in leaf Mn concentrations was detected, below the levels found in control soils. For this reason, in soils with high Cu-concentrations, although mycorrhizal inoculation can be a suitable strategy to improve plant growth and nutrition, the use of EDTA-based products should be avoided, as it can lead to an amplification of the toxic effects commonly caused by the excess of Cu in plants.

Effect of Some Rootstocks on the Performance of Flame Seedless Grapevines

Effect of Some Rootstocks on the Performance of Flame Seedless Grapevines

Optimization of Vineyard Water Management: Challenges, Strategies, and Perspectives

Water availability is endangering the production, quality, and economic viability of growing wine grapes worldwide. Climate change projections reveal warming and drying trends for the upcoming decades, constraining the sustainability of viticulture. In this context, a great research effort over the last years has been devoted to understanding the effects of water stress on grapevine performance. Moreover, irrigation scheduling and other management practices have been tested in order to alleviate the deleterious effects of water stress on wine production. The current manuscript provides a comprehensive overview of the advances in the research on optimizing water management in vineyards, including the use of novel technologies (modeling, remote sensing). In addition, methods for assessing vine water status are summarized. Moreover, the manuscript will focus on the interactions between grapevine water status and biotic stressors. Finally, future perspectives for research are provided. These include the performance of multifactorial studies accounting for the interrelations between water availability and other stressors, the development of a cost-effective and easy-to-use tool for assessing vine water status, and the study of less-known cultivars under different soil and climate conditions.

The effects of field inoculation of arbuscular mycorrhizal fungi through rye donor plants on grapevine performance and soil properties

Grapevines are highly dependent on arbuscular mycorrhizal fungi (AMF) for normal growth and development. However, vineyard soils may have low AMF abundance and diversity due to conventional soil management practices that are detrimental for these fungi. In this context, the establishment of AMF-inoculated cover crops can be a highly convenient strategy to reestablish soil mycorrhizal potential, as it combines the advantages of a vigorous inoculum source coming from mycorrhizal donor plants with the overall benefits of green covers for grape quality, microbial diversity and soil health. In this work, the potential benefits of Funneliformis mosseae-inoculated under-vine cover crops on grapevine growth, physiology and production were compared to those derived from 1) the establishment of non-inoculated under-vine cover crops, and 2) conventional herbicide-based weed control in the under-vine space. In addition, grapevine root AMF community composition was analyzed to assess if the introduction of a non-native AMF species induced changes on resident mycorrhizal community assemblies and to unveil potential variations in AMF diversity associated to herbicide replacement by green covers. Results indicated that under-vine cover crops, inoculated or not, led to a general vigor decrease in grapevines, probably due to competition between the two species. However, after a heat wave that occurred at harvest time in the second year of the experiment, grapevines growing in plots with inoculated cover crops had the highest photochemical reflectance indices and net photosynthesis rates, and partially compensated production losses due to berry sunburn. Root mycorrhizal community analysis by the end of the experiment revealed that the inoculated F. mosseae isolate colonized grapevine roots from inoculated plots, while it was absent in the other ones. Moreover, inoculation of this AMF did not lead to a replacement of native root AMF communities, but allowed further colonization by other resident Glomeraceae and non-Glomeraceae AMF taxa. Overall, the work herein demonstrates that the introduction of F. mosseae through donor plants is a suitable field inoculation method for grapevines and can help them to better withstand heat waves.

Application of Fractions of Crop Evapotranspiration Affects Carbon Partitioning of Grapevine Differentially in a Hot Climate

Majority of viticulture regions are located in mid-latitudes characterized by weather variability and stressful environments relying on irrigation for mitigating environmental stress during the growing season and to ensure a profitable yield. The aim of this study was to characterize the response of grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) to different applied water amounts based on the replacement of fractions of crop evapotranspiration (ETc) during two growing seasons with contrasting precipitation patterns. The experiment consisted of three irrigation treatments based on the weekly replacement of 25, 50, and 100% of ETc. Grapevine stem water potential decreased during the growing season reaching its lowest value (-1.5 and -1.2 MPa, respectively) at harvest in the more stressed vines (25 and 50% ETc). Leaf gas exchange variables were measured during the two seasons and 100% ETc had the highest rates of photosynthesis and stomatal conductance and better instantaneous water use efficiency, also resulting in higher leaf chlorophyll and carotenoid content. Mineral nutrient content for nitrogen and potassium increased linearly with the increase in applied water. At harvest, no differences were observed in the number of clusters per vine; however, the 25% ETc had the lowest berry size and yield per vine with no difference in sugar content of berry. Conversely, sugar allocation to reserve organs was highly affected by applied water leading to different shoot to root biomass partitioning, where shoot:root ratio, leaf non-structural carbohydrates, and photosynthetic pigments increased with greater applied water. Likewise sucrose:N ratio and root non-structural carbohydrates decreased with the lower applied water. Altogether, carbon allocation between the source and sink organs likely controlled the response of grapevines to water deficits in a hot climate, and replacing 50% ETc was sufficient to sustain the grapevine performance given the enhancement of sugar transport, which could slow down the detrimental effect of water deficits on yield.

Gas exchange, vine performance and modulation of secondary metabolism in Vitis vinifera L. cv Barbera following long-term nitrogen deficit

Main ConclusionA reprogramming of secondary metabolism to acclimate to nitrogen deficiency was seen in grapevine eliciting an accumulation of strigolactones and jasmonate. This response links with photosynthetic compensation and enhanced ripening.In addition to the metabolism directly related to nitrogen assimilation, long-term nitrogen depletion may affect plant secondary metabolism, in turn affecting grapevine performance. In this work, the effect of nitrogen deficit was investigated in V. vinifera cv. Barbera potted vines following three years of deprivation, using a combination of morpho-physiological assessments and mass spectrometry-based untargeted metabolomics. Plants grown under nitrogen limitation showed reduced growth and even more curtailed yields, lowered SPAD values, and a quite preserved leaf gas exchange, compared to plants grown under non-limiting nitrogen availability. Ripening was decidedly accelerated, and berry composition improved in terms of higher sugar and phenolic contents under nitrogen-limiting conditions. Metabolomics showed the broad involvement of secondary metabolism in acclimation to nitrogen deficiency, including a distinctive modulation of the phytohormone profile. Several nitrogen-containing metabolites were down accumulated under nitrogen-limiting conditions, including alkaloids, glucosinolates, hypoxanthine, and inosine. On the other hand, phenylpropanoids showed an accumulation trend. Concerning the recruitment of hormones, nitrogen deprivation elicited an accumulation of strigolactones and jasmonate. Noteworthy, both strigolactones and jasmonates have been previously related to increased photosynthetic efficiency under abiotic stress. Furthermore, the severe reduction of lateral shoot development we recorded in N-deprived vines is consistent with the accumulation of strigolactones. Overall, our results suggest that nitrogen deprivation induced a rather broad metabolic reprogramming, mainly including secondary metabolism and hormones profile, reflected in the modulation of photosynthetic performance, canopy growth, and possibly fruit quality.

Cover Crop and Pruning Residue Management to Reduce Nitrogen Mineral Fertilization in Mediterranean Vineyards

This paper aimed to study the effect of temporary cover crop and vine pruning residue burial as alternative practices to conventional tillage on soil nitrate (NO3-N) availability and grapevine performance in the short term. The trial was carried out in a rain-fed vineyard (Vitis vinifera L., cv Grecanico dorato/140 Ruggeri) located in a traditional Mediterranean viticultural area (37°32′48′′ N; 13°00′15′′ E) in Sicily (Italy). Conventional tillage (CT) soil management was compared with winter cover crop (CC), conventional tillage plus buried pruning residue (CT + PR), and winter cover crop plus buried pruning residue (CC + PR) management treatments. Two fertilizer treatments (92 kg ha−1 of N as urea and 0 kg ha−1) were applied to the four soil management treatments. Vicia faba L. was the selected leguminous cover crop species, which was seeded in autumn and buried in spring at the same time as vine pruning residues. The soil NO3-N content was monitored, and vine vegetative growth, yield, and must quality were assessed over two seasons. Results showed that NO3-N availability strongly differed between fertilized (F) and unfertilized (UF) plots and years and among treatments. A positive effect of winter leguminous CC + PR on the Grecanico dorato grapevine performance was observed. In the UF vineyard, grape fertility, yield, Ravaz index, and total soluble solids were significantly higher in CC + PR vines than in other treatments, thus showing the reliability of reducing N mineral fertilization and related risks of excess nitrate in groundwater. The possibility of increasing the overall sustainability of rain-fed vineyards in a semiarid agro-ecosystem, without negative effects on grape and must quality, is also demonstrated.

Effects of leaning grapevine canopy to the West on water use efficiency and yield under Mediterranean conditions

This study tested the possibility of improving whole-canopy water use efficiency (WUE) of grapevines (cv. Bobal) by maximizing radiation interception during the mornings and limiting this during the afternoons, when the vapour pressure deficit and the evaporative demand are higher. The three-year study consisted of two trials conducted in parallel on North-South row oriented potted- and field-grown grapevines. In both trials, performance in terms of vine water use, yield and WUE in a vertical shoot positioned (VSP) system was compared with that of vines leaned 30° towards West (WSP). Potted vines were fully irrigated, whereas field-grown vines were submitted to rain-fed and deficit irrigation conditions. In potted plants, there was no difference in daily transpiration between vines from the WSP and VSP treatments, but transpiration in the mornings was higher in WSP vines. Dry matter and berry size increased in WSP compared to VSP vines. In the field, watering regime had a greater effect than canopy inclination on vine performance. Nonetheless, the WSP system increased leaf area by 13%, yield by 12% and WUE by 11% compared to VSP, although differences in WUE were not statistically significant and the effect on yield was negligible under rain-fed conditions. In both trials, the WSP system did not have a major effect on grape composition (soluble solids, pH, total acidity, concentrations of anthocyanins and polyphenols). In conclusion, this pioneering three-year study proved that leaning vine canopies to the West increased grapevine performance despite the great effect that environmental conditions exerted each year on the data obtained. Further research is required to study the effects of different patterns of light interception on carbon balance and grape biochemical composition.

AMF communities associated to Vitis vinifera in an Italian vineyard subjected to integrated pest management at two different phenological stages

Vitis vinifera L. is an economically important crop that can be influenced by soil microorganisms, including arbuscular mycorrhizal fungi (AMF), that establish symbiotic associations with its roots. AMF have beneficial effects on grapevine performance improving water use efficiency and replant success. Most grapevine varieties are susceptible to various diseases, and integrated pest management (IPM) is one of the emerging approaches to perform pest control. In the present study, we examined the AMF communities present in the soil associated to the roots of V. vinifera cv. Pinot Noir (comparing them to those present in a soil not affected by grapevine roots), in a vineyard subjected to IPM at two different phenological stages, using 454 Roche sequencing technology. We proposed a new approach to analyze sequencing data. Most of the taxa were included in the family Glomeraceae. In particular, Glomus sp. Rhizophagus sp. and Septoglomus viscosum were present. The family Archeosporaceae was represented only by the genus Archeospora sp. Different AMF communities were found in the two soils and the importance of the phenological stage in regulating AMF biodiversity was assessed.

Performance of grapevine grown on reclaimed Mediterranean karst land: Appearance and duration of high temperature events and effects of irrigation

Stony karst landscape in the Adriatic coastal area has been cultivated for centuries to grow Mediterranean crops. Shallow and less fertile soils were mostly used for rain-fed grapevine and olive production. Native grapevine cultivars are, in general, well adapted to the warm and droughty climate, but a rapid drift in weather patterns characterized mostly by long-lasting high temperature events during the growing season urges the producers to apply irrigation. This research, studying the effects of different irrigation levels on Babić grapevine performance, was carried out in two growing seasons (2015 and 2016) with contrasting weather conditions in a vineyard established on a parcel of land derived from the stony surface of a limestone plateau on the very edge of the Eastern Adriatic coast. The study evaluated the effects of different irrigation regimes based on the quantification of grapevine water use (50, 75, and 100 % of crop evapotranspiration) by measuring the total leaf area, leaf gas exchange performance, and grape yield and quality. The irrigation treatments increased the total leaf area, net photosynthetic rate, average transpiration rate, and average mesophyll CO2 concentration. The yield components and grape quality were also affected by the irrigation treatments. Positive effects of irrigation in both the experimental seasons were associated with increased yield and total soluble solids (TSS), as well as synchronized TSS and phenolic ripening. Furthermore, water stress positively affected the concentrations of anthocyanins and other polyphenols in both years of the study. In 2015, extremely high temperatures reduced the grape yield, juice yield, and anthocyanin content in grapes in non-irrigated vines as well as in all irrigation treatments. Irrigation was efficient in reducing these negative effects, except in the case of the anthocyanin content.

Fertilization by Nano-powder Potassium Sulfate enhancing Production of Grapevines cv. Crimson Seedless

ABSTRACT A field experiment was conducted in a randomized complete design with three doses of Nano-powder potassium sulfate(100, 150 and 200 g per vine) and one dose of traditional potassium sulfate (200 g per vine), which applied as soil applications to compare the effect of potassium at nano or traditional form on the performance of Crimson seedless grapevines during 2018 and 2019 seasons. Results revealed that the Nano-powder potassium sulfateat 150 and 200g per vine was better than the traditional form in enhancing vegetative growth, nutrient uptake, cluster quality and yield of Crimson seedless grapevines. In summary, it can be concluded that utilizing a nano form of potassium sulfate at an equal dose of traditional form or by less than fifty gram lead to an increase in the productivity of Crimson seedless grapevines.

Protein hydrolysates effects on grapevine (Vitis vinifera L., cv. Corvina) performance and water stress tolerance

The effects of animal- and plant-derived protein hydrolysates (PHs), namely casein (Cas), soybean (Soy) and lupin (Lup), in improving grapevine performance and inducing water stress tolerance were evaluated in the field on the wine grape cultivar Corvina. PHs were applied every ten days and for three times from fruit-set to bunch closure by spraying at two concentrations (1.6 and 6.4 g L−1 equivalent to 0.5 and 2.0 kg/ha, respectively); water treatment was used as control. Overall, data clearly pointed out the effect of biostimulants in enhancing grapevine yield and quality and in reducing conductance index (IG), with differences in efficiency, depending on the biostimulant origin and concentration. With regards of yield, Soy and Cas at 6.4 g L−1 reached 5.57 and 5.39 kg/vine, respectively, with an increase of 24 and 21% with respect to the control treatment (4.25 kg/vine). Total soluble solids content was significantly increased by PHs application, with values ranging from 19.05 (control) up to 22.80 °Brix (Lup at 1.6 g L−1). All PHs significantly ameliorated the total anthocyanin content of berries with respect of the control (132 g L−1). The best effect was obtained by Cas treatment at the lower dose with an anthocyanin content of 373 g L−1. Generally, canopy temperature of treated vines remained significantly higher than untreated control of 1–3 °C degrees. Regarding water stress tolerance, the lowest dose of Soy- and Cas-PHs showed great ability to reduce the stress index IG (proportional to stomatal conductance). This 5-year study showed the role of PHs, as natural biostimulants, to ameliorate fruit parameters and reduce water loss and Soy- and Lup-PHs can be considered for a commercial application.

Prospecting intercropping between subterranean clover and grapevine as potential strategy for improving grapevine performance

Intercropping is an agricultural practice commonly used to improve plant nutrition. In this study, we prospected the interaction between root exudates of subterranean clover (Trifolium subterraneum L.) and grapevine (Vitis vinifera L.). This experiment was focused on the detection of organic acids, amino acids, and flavonoids in root exudates released by grapevine and subterranean clover grown separately and together. Furthermore, we quantified low-molecular-weight organic acids (LMWOA) in root exudates. To test the effect of root exudates in plant-plant chemical signaling, both species were grown in Hoagland hydroponic solution. The experimental design contained three treatments: T1 (subterranean clover, monocropping); T2 (grapevine, monocropping) and T3 (subterranean clover + grapevine, intercropping). The exudate profile showed that the main compounds were amino acid, flavonoids and organic acids in all treatments. Specifically, amino acids exudates (∼20%) were l-threonine by subterranean clover in monocropping (T1) and glutathione in intercropping with grapevine (T3). Glycylglycine was detected in exudates released by subterranean clover (T1) and both plants under intercropping (T3). Regarding flavonoids (∼10%), epicatechin was detected only in subterranean clover exudates (T1). Interestingly, we detected kaempferol-3-glucuronide, l-2-aminoadipic and gluconic acids were found only under intercropping. The LMWOA were oxalic, malic, citric, and succinic. Oxalic acid was released in higher concentration. We highlight that succinic acid reached the highest concentration under intercropping on day-30. These results strongly suggest that amino acids, flavonoids and organic acids acts as signaling compounds between plant-plant interaction, can be utilized for improving grapevine plant performance.

Influence of Canopy Management Practices on Canopy Architecture and Reproductive Performance of Semillon and Shiraz Grapevines in a Hot Climate

Canopy management techniques can be beneficial to grapevine reproduction because they improve canopy structure and microclimate. In this study, the influence of different canopy management practices—cluster thinning, leaf removal, shoot-thinning, and light pruning—on reproductive performance was studied for the varieties Semillon and Shiraz grown under field conditions in a hot climate in South Australia. Canopy architecture, canopy light interception, and reproductive parameters for different management practices were measured. Results showed that the applied practices modified canopy architecture and influenced reproductive performance and the berry ripening process. Specifically, shoot-thinning and leaf removal decreased leaf area index and increased canopy porosity and light interception. Berry ripening was positively affected by cluster thinning and shoot-thinning, while leaf removal and light pruning delayed the process. For reproductive parameters, leaf removal had a relatively minor effect; shoot-thinning and cluster thinning reduced cluster number but showed compensation effects in other yield components, and light pruning decreased berry weight. In addition, cluster compactness was found to be significantly correlated with bunch rot (Botrytis cinerea) incidence for Semillon.

Row orientation effects on Syrah grapevine performance during winter growing season

ABSTRACT The sunlight and heating effects on leaves and grapes are directly influenced by row orientation in vineyards. Row orientation studies have not been addressed under double pruning management, a technique used to transfer the wine grape harvest from wet summer to dry winter season in Brazilian Southeast. Effects of grapevine row orientation (north/south - NS and east/west - EW) of vertically trellised and shoot positioned Vitis vinifera L. Syrah grafted onto 1103 Paulsen were investigated in the South of Minas Gerais State. The vegetative vigor was increased in NS oriented vines, probably due to high photosynthesis as suggested by the highest leaf starch accumulation. The leaf and stem water potential were slight affected by row orientation. NS orientation increased the cluster weight, but cluster number and yield per vine were not affected by treatments. Berries from NS oriented vines also showed the highest values of anthocyanins and total phenols. Under NS orientation there was a reduction on tartaric acid and soluble sugar in berries probably diluted by increased cluster weight. This study showed that vineyard under NS orientation improved grapevine vigor and promoted better phenolic maturity in wine grapes harvested during the winter season than EW orientation.

Mapping vineyard vigor using airborne remote sensing: relations with yield, berry composition and sanitary status under humid climate conditions

The aim of this study was to assess the spatial variability of plant vigor in a vineyard in a humid climate. Normalised Difference Vegetation Index (NDVI) was used for relating the vigor level to grapevine performance and, as a new area, with the anthocyanin and organic acid compositions of the berries. The study was performed in a rain-fed vineyard with the Tannat cultivar, vertically trellised, during three consecutive vintages (2015–2017). NDVI was estimated from high-resolution images acquired using airborne sensors, which allowed differentiation of three vigor levels within the vineyard: high, medium and low. Three plots per vigor level were installed for performing samplings and field measurements. High vigor zones were associated with less water-stressed vines, higher yields, incidence of bunch rot, larger berries, total acidities and total anthocyanins concentrations. Low vigor zones corresponded to higher pH, soluble solids and phenolic contents in the berries. Medium vigor zones were associated with higher leaf surface, pruning weights, cluster average weights and greater extractable anthocyanins concentrations. The effect of weather conditions of each growing season on grapevine water status was a major factor influencing the analysed variables. NDVI values allowed for delineating areas with homogeneous vigor within the vineyard, which corresponded with different plant performance, showing the usefulness of this tool for site-specific management under the studied conditions.

Mycorrhizal Inoculation Differentially Affects Grapevine's Performance in Copper Contaminated and Non-contaminated Soils.

Plant inoculation with arbuscular mycorrhizal fungi (AMF) is increasingly employed to enhance productivity and sustainability in agricultural ecosystems. In the present study, the potential benefits of AMF inoculation on young grapevines replanted in pots containing vineyard soil with high Cu concentration were evaluated. For this purpose, one-year-old cv. Touriga Nacional grapevines grafted onto 1103P rootstocks were further inoculated with Rhizoglomus irregulare or Funneliformis mosseae, or left non-inoculated, and maintained in a sterilized substrate under greenhouse conditions for three months. After this time, half of the plants were transplanted to containers filled with an Arenosol from a vineyard which had been artificially contaminated or not with 300 mg kg−1 of Cu. At the end of the growing season, soil nutrient concentration, soil dehydrogenase activity and mycorrhizal colonization rate were analyzed. Grapevine performance was assessed by measuring several vegetative growth and physiological parameters as well as nutrient concentrations in leaves and roots. In the non-contaminated soil, R. irregulare- and F. mosseae-inoculated plants had significantly greater root biomass than the non-inoculated ones. However, the opposite effect was observed in the Cu-contaminated soil, where non-inoculated plants performed better regarding shoot and root development. Concerning nutrient levels, an increase in Cu, Mg and Mn concentrations was observed in the roots of plants growing in the contaminated soil, although only Mn was translocated to leaves. This led to a large increase in leaf Mn concentrations, which was significantly higher in non-inoculated and F. mosseae- inoculated plants than in the R. irregulare- inoculated ones. Copper contamination induced a general decrease in leaf N, P and Fe concentrations as well as chlorosis symptoms. The largest decrease in N and P was observed in F. mosseae- inoculated plants, with 73 and 31.2%, respectively. However, these plants were the ones with the least decrease in Fe concentration (10% vs. almost 30% in the other two inoculation treatments). In conclusion, this study indicates that soil Cu levels can modify the outcome of AMF inoculations in young grapevines, disclosing new AMF-plant associations potentially relevant in vineyards with a tradition of Cu-based fungicide application.

Influence of pedoclimatic factors on grapevine performance and berry ripening: Preliminary results of Chardonnay grown in Friuli Venezia Giulia region, Italy

The concept of terroir is widely used in the wine industry, and many studies are undertaken to better understand the influence of local terrain features on produced wines. In this context, this study monitored nine Chardonnay plots in the Fruili wine region of Italy to gather information on grapevine growth and berry ripening. The study objective was to define viticulture potentialities allowing to identify future strategies for the production of a “single vineyard” Chardonnay wine at the Vie di Romans estate, Italy. During the growing season of 2017, relations were studied between terrain features and field observations on vine phenology and grape ripening. Stem water potential and gas exchange measurements were also effectuated. Results show that there are significant differences between the studied plots. Earliness of the grapevine cycle between the plots has been less evident to determine than the variation in berry characteristics. The latter were linked with identified pedoclimatic units, but the effect of the cultural practices should not be overlooked. The study should be perceived as a first monitoring campaign, highlighting the important differences between study plots. Further investigation in the following seasons should give a more accurate perception of individual plot characteristics and their impacts.

Impact of delayed winter pruning on phenology and ripening kinetics of Pinot Noir grapevines

Climate change impacts viticulture with even stronger effects on sparkling wines. Innovative cultural practices represent effective short-term solutions. Among these, postponement of winter pruning later than budburst delayed both vegetative and reproductive cycles as well as technological maturity of several varieties from different wine regions. This research aims to assess the impact of delayed winter pruning on grapevine performance as a function of training system.The trial was carried out in a Pinot Noir vineyard sited at 385 m asl in Central Italy. Delayed winter pruning was performed when unpruned canes had shoots showing three unfolded leaves (BBCH 13) and compared to standard winter pruning within two separate experiments focused on: i) cane pruning, and ii) spur pruning. Grapevine phenology, vegetative growth, fruit ripening kinetics and productivity of selected vines were assessed over three years. Delayed winter pruning postponed budburst by 20 and 31 days in Guyot and spur pruned cordons, respectively; then, differences diminished over time showing a maximum delay of 17 days at bloom and 7–10 days at harvest. Despite a decrease in yield (ranging from −35 to −47% in cane and spur pruning, respectively), delayed winter pruning increased titratable acidity (40–89%) and reduced sugars (721%) as compared to control vines. Although effects of delayed pruning were stronger in spur pruned vines, delayed winter pruning was effective also on cane-pruned vines, therefore adapting to varieties marked by low basal-node fruitfulness