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Societal Impact Statement Summary The innumerable effects of terroir—including climate, soil, microbial environment, biotic interactions, and cultivation practice—collectively alter plant performance and production. A more direct agricultural intervention is grafting, in which genetically distinct shoot and root genotypes are surgically combined to create a chimera that alters shoot performance at a distance. Selection of location and rootstock are intentional decisions in viticulture to positively alter production outcomes. Here, we show that terroir and rootstock alter the shapes of grapevine leaves in commercial vineyards throughout the California Central Valley, documenting the profound effects of these agricultural interventions that alter plant morphology. Embedded in a single leaf shape are the latent signatures of genetic, developmental, and environmental effects. In viticulture, choice of location and rootstock are important decisions that affect the performance and production of the shoot. We hypothesize that these effects influence plant morphology, as reflected in leaf shape. We sample 1879 leaves arising from scion and rootstock combinations from commercial vineyards in the Central Valley of California. Our design tests 20 pairwise contrasts between Cabernet Sauvignon and Chardonnay scions from San Joaquin, Merced, and Madera counties from vines grafted to Teleki 5C, 1103 Paulsen, and Freedom rootstocks. We quantify clear differences between Cabernet Sauvignon and Chardonnay leaves. However, we also detect a separate, statistically independent source of shape variance that affects both Cabernet Sauvignon and Chardonnay leaves similarly. We find that this other shape difference is associated with differences in rootstock and location. The shape difference that arises from rootstock and location affects the basal part of the leaf near the petiole, known as the petiolar sinus, and affects its closure. This shape effect is independent from previously described shape differences that arise from genetic, developmental, or size effects. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary The cultural significance of the grapevine is undeniable. However, we fail to acknowledge how the grapevine has and continues to influence the most pressing political questions of our time. From the beginning of the Conquest, Indigenous peoples were forced to plant the vine, Spain burned the vines Miguel Hidalgo used to teach the poor, and César Chávez and the Delano grape strike demanded justice for agricultural laborers. From the Grito de Dolores to Sí se puede, we demonstrate how the continuing relationship between Mexico and the grapevine influences debates surrounding labor, immigration, and human rights in the United States and throughout the world. To enhance the reach of this work, a Spanish language version of the paper is available in the Supporting Information (see Translation_ES).The wild grapevine species (Vitis spp.) that comprise the pedigrees of rootstocks, the Americas as the source (and solution) to the Phylloxera crisis that decimated European vineyards, and California as a premier wine‐growing region are the topics that usually frame the history of grapes in North America. This Anglo‐American perspective ignores that domesticated grape varieties were first introduced to North America in what is now Mexico and the singular contributions of Mexican labor to the California wine economy that continue to influence politics. Here, we highlight the neglected history of grapevines in Mexico and argue that the politics of labor that played out during the Conquest never ceased and still shape debates surrounding immigration. Beginning with Hernán Cortés, Indigenous peoples were forced to plant grapevines and when they were successful, they were abruptly forbidden by Spain to grow grapes. This interference influenced Miguel Hidalgo, who taught the poor viticulture as a trade and who would lead the Mexican War of Independence and pay with his life. The grapevine continued its journey north to California, where Franciscans established the missions and cultivated the Mission grapes, which had lasting impacts on the genetics of grapevine varieties. Finally, it was the Delano grape strike that coalesced César Chávez and the United Farm Workers to demand justice for agricultural laborers that is the foundation of the California wine economy and still shapes the current political debate of immigration, labor, and human rights between the United States and Mexico. [ABSTRACT FROM AUTHOR]

The D14 protein, an alpha/beta hydrolase, is a key receptor in the strigolactone (SL) signaling pathway. However, the response of VvD14 to SL signals and its role in grapevine root architecture formation remain unclear. This study demonstrated that VvD14c was highly expressed in grapevine tissues and fruit stages than other VvD14 isoforms. Application of GR24, an SL analog, enhanced the elongation and diameter of adventitious roots but inhibited the elongation and density of lateral roots (LRs) and increased VvD14c expression. Additionally, GR24 is nested within the VvD14c pocket and strongly bound to the VvD14c protein, with an affinity of 5.65 × 10−9 M. Furthermore, VvD14c interacted with grapevine MORE AXILLARY GROWTH 2 (VvMAX2) in a GR24-dependent manner. Overexpression of VvD14c in the d14 mutant and VvMAX2 in the max2 Arabidopsis mutant reversed the increased LR number and density, as well as primary root elongation. Conversely, homologous overexpression of VvD14c and VvMAX2 resulted in reduced LR number and density in grapevines. VvMAX2 directly interacted with LATERAL ORGAN BOUNDARY (VvLOB) and VvLBD19, thereby positively regulating LR density. These findings highlight the role of SLs in regulating grapevine root architecture, potentially via the VvD14c-VvMAX2-VvLOB/VvLBD19 module, providing new insights into the regulation of root growth and development in grapevines. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Wine production has a significant impact on the global economy. Despite this, the microbial composition of the terroir has not been studied sufficiently, particularly in the southern hemisphere. Here, we investigated how bulk soil fungal communities are affected by several abiotic and biotic factors across 1,000 km of Chilean vineyards. We found that geographical distance was the main driver of vineyard soil fungal communities. Irrespective of variety, older vineyards host a higher relative abundance of arbuscular mycorrhizal fungi (AMF) and a lower relative abundance of plant pathogenic fungi. This result could lead to significant recommendations on when to apply AMF‐based inoculants. The microbial dimension of the terroir has been increasingly recognized as an essential factor determining vineyard productivity and quality. Despite this, few studies have analyzed the factors affecting soil fungal communities of vineyards in the southern hemisphere. Across a 1,000 km gradient encompassing 34 Chilean vineyards, we investigated the effects of grapevine variety, geographical distance, maturity, and soil chemical properties on the diversity and composition of soil fungi. We implemented standard soil chemical analyses and ITS‐based DNA metabarcoding of bulk soil. We found that the total soil fungal composition was significantly affected by geographical distance but not by grapevine variety and maturity. Soil chemical dissimilarity also significantly affected soil fungal composition. When analyzing specific fungal guilds, we found a contrasting successional pattern: arbuscular mycorrhizal fungal relative abundance was significantly higher at medium and old‐maturity vineyards compared with young vineyards, on which plant pathogenic fungi had a markedly lower abundance. Our results present several caveats: the molecular marker was not the most commonly used for arbuscular mycorrhizal fungi, bulk soil was sampled (instead of roots), and all abundances were relative. Still, this study constitutes one of the most extensive studies on soil fungi – both for vineyards and Chile – and might have practical implications, as knowing the drivers of fungal and mycorrhizal biodiversity can inform agricultural management decisions. [ABSTRACT FROM AUTHOR]

Abstract The D14 protein, an alpha/beta hydrolase, is a key receptor in the strigolactone (SL) signaling pathway. However, the response of VvD14 to SL signals and its role in grapevine root architecture formation remain unclear. This study demonstrated that VvD14c was highly expressed in grapevine tissues and fruit stages than other VvD14 isoforms. Application of GR24, an SL analog, enhanced the elongation and diameter of adventitious roots but inhibited the elongation and density of lateral roots (LRs) and increased VvD14c expression. Additionally, GR24 is nested within the VvD14c pocket and strongly bound to the VvD14c protein, with an affinity of 5.65 × 10−9 M. Furthermore, VvD14c interacted with grapevine MORE AXILLARY GROWTH 2 (VvMAX2) in a GR24-dependent manner. Overexpression of VvD14c in the d14 mutant and VvMAX2 in the max2 Arabidopsis mutant reversed the increased LR number and density, as well as primary root elongation. Conversely, homologous overexpression of VvD14c and VvMAX2 resulted in reduced LR number and density in grapevines. VvMAX2 directly interacted with LATERAL ORGAN BOUNDARY (VvLOB) and VvLBD19, thereby positively regulating LR density. These findings highlight the role of SLs in regulating grapevine root architecture, potentially via the VvD14c-VvMAX2-VvLOB/VvLBD19 module, providing new insights into the regulation of root growth and development in grapevines.

Background and aims: A better understanding of plant carbon assimilation, water status and photosystem performance responses to combined heat and drought stress would help to optimize grapevine management under such limiting conditions. Methods: Gas exchange and chlorophyll fluorescence parameters were measured in potted grapevines, cv Sauvignon Blanc, before, during and after simulated six-day heat (Tmax = 40 °C) wave using heated well-watered (HW), heated drought-stressed (HD), non-heated well-watered (CW) and non-heated dry (CD) vines. Results: Photosynthesis and stomatal conductance in HW vines increased during the morning and dropped in the afternoon with respect to CW vines. Daily plant transpiration in HW almost doubled that of CW vines. When grapevines were already exposed to drought, the effects of the heat wave were negligible, with HD plants showing similar leaf photosynthesis and transpiration to their CD counterparts. Heat, but not drought stress, decreased the maximum (Fv/Fm) and effective photochemical quantum yield of PSII (φPSII), and also affected the use of absorbed energy. HW plants dissipated more radiative energy as heat, a protective mechanism of the photosystem, while HD vines increased the energy dissipated by non-regulated non-photochemical pathways, which might lead to photoinhibition damages. The different behavior could be due to the enhanced transpiration rate and consequent decrease in leaf temperature in HW as compared to HD vines. After the heat wave, only HW vines recovered the afternoon values of photosynthesis, stomatal conductance and φPSII to similar levels as those in CW vines. Conclusion: Drought had a more significant effect than heat stress on photosynthesis, stomatal conductance and transpiration. The combined heat and drought stress, however, increased the proportion of energy lost by the leaves through harmful non-regulated dissipative pathways. With adequate soil water availability, grapevines withstood the heat wave period through an increase in leaf transpiration, which decreased leaf temperature and protected the PSII from heat damage. Highlights: Drought had a stronger impact on gas exchange parameters than elevated temperature during a simulated heatwave, while heat stress was the main driver of PSII functionality and absorbed energy partitioning. Well-watered grapevines were able to recover their physiological function after a six-day heatwave (Tmax 40 °C), while plants under heat and drought stress were unable to resume PSII performance after one day of recovery. [ABSTRACT FROM AUTHOR]

The present work aimed to evaluate green-nano manganese produced at the Microbial Biotechnology Department, National Research Centre, Egypt, and assess its impact on the growth, yield, and fruit properties of grapevines. To this end, two experiments were conducted. The first was microbiological, where several incorporation strategies were utilized to enrich the yeast with manganese, as follows: (1) manganese was added to the liquid medium (non-growth phase), and (2) manganese was added after 24 h of incubation (growth phase). The results showed that the non-growth phase had a reduced possibility of medium contamination. The manganese concentration in the yeast cells was increased due to manganese sulfate in the medium. The manganese incorporation in yeast cells was 99.93% (1.205 × 105) higher than that of the medium at 0.0195 g/L of manganese. Although the concentration of manganese in the medium raised the optical density (OD) of the yeast cell biomass, manganese sulfate had no passive influence on it. The second experiment was horticultural, where Flame Seedless grapevines were sprayed with frozen and active fresh yeast enriched with manganese that resulted from the microbiological experiment. Grapevines were sprayed twice a year at 10 or 20 cm3/L, and the results were compared with those for the mineral and chelate forms. The results demonstrated that yeast extracts in both forms showed positive effects on grapevine. The most effective treatment with regard to growth, yield, and fruit properties was frozen yeast enriched with manganese at 20 cm3/L, which yielded 10.14 and 12.6 kg/vine, compared with the control, which recorded 3.7 and 5.6 kg/vine in the two seasons, respectively. [ABSTRACT FROM AUTHOR]

Traditional methods for assessing vine water status, such as the Scholander pressure chamber, are time-consuming, punctual and labour-intensive. The development of alternative methods which are accurate, reliable and can provide real-time information on vine water status is a necessity for farmers all over the world. This study proposes the use of plant electrophysiology as a novel approach for real-time water status assessment in grapevines. We conducted four climate chamber experiments with potted grapevines under different irrigation regimes. Various morphological and physiological assessments were performed in parallel with electrophysiological measurements to correlate classic water status assessment methods with plant electrophysiological signals. Two machine learning approaches based on classification and regression were employed to train the prediction models. Results obtained from both models indicate significant differences in irrigation status between well-watered and water-deficit plants, with the latter showing reduced growth and physiological activity, confirming the water stress status of the plant. While the binary classification model successfully differentiates between well-watered and water-deficit plants, its practical use is limited. Therefore, a regression model was developed to directly predict predawn leaf water potential. To the best of our knowledge, this is the first time that electrical signals are correlated with vine water potential measurements. The findings presented here thus provide a promising new tool for future real-time and remote monitoring of vine water status to manage irrigation and adapt agronomic strategies. Nevertheless, validation and optimisation of the models are still necessary, particularly under field conditions.

Comparative measurements of four Vitis vinifera cultivars were undertaken to assess assimilation tolerance to the high growth temperatures currently pervading Australian and other wine growing regions. The cultivars, cvs. Chardonnay, Merlot, Semillon, and Shiraz, were all grown in common growth conditions, and an hypothesis promulgated genotypic variation in assimilation and in the leaf temperature dependency. Assimilation responses to varying light intensity and to varying chloroplast CO2 at a range of leaf temperatures (15–45°C) were measured in leaves of each cultivar in mid‐summer. Light response curves revealed marked genotype differences in maximum assimilation, but temperature effects also varied. Semillon leaves were most sensitive to temperature, with marked and steep differences in assimilation at different temperatures while Chardonnay and Merlot were least sensitive, with relatively flat responses. There were also marked cultivar differences in response to CO2 and significant effects of leaf temperature. CO2‐saturated assimilation varied markedly, with Semillon and Merlot leaves most responsive to temperature, although there were differences in optimum temperatures and maximum rates. Chardonnay leaves remained least tolerant, with lowest rates of assimilation across most temperatures. Assimilation at 45°C also separated the cultivars and two cultivars had higher rates than at 15°C while Chardonnay and Merlot leaves had higher rates at 15°C. There were no cultivar differences in the temperature dependency of Ribulose 1,5‐bisphosphate (RuBP) carboxylation, but Semillon had a much steeper temperature dependency on RuBP regeneration than the other cultivars. All these responses confirmed the hypothesis and concluded the high‐temperature tolerance of Semillon and Shiraz and the poor adaptability of Chardonnay and possibly Merlot to perform in the current high‐temperature growth conditions. [ABSTRACT FROM AUTHOR]

In this study, the cold hardiness degrees of the main grape cultivars grown in the temperate climatic conditions of Samsun province, Turkiye were determined using the tissue browning technique. Winter canes were prepared as single nodes cuttings in the coldest month of February. After an artificial freeze test, LT50 degrees of primary, secondary, tertiary buds, and phloem tissue were determined. In addition, after the freeze test, some growth and rooting parameters of single-bud cuttings were examined in a growing room condition. The highest LT50 values in primary, secondary, and tertiary buds were observed in 'Karaerik', 'Alphonse Lavallee', 'Çeliksu' and 'Merzifon Karası' cultivars. Highest primary bud LT50 values were obtained as – 24.3 °C in 'Karaerik', – 23.1 °C in 'Çeliksu', – 22.9 °C in 'Alphonse Lavallee', and – 22.1 °C in 'Merzifon Karası' cultivars. The lowest primary bud LT50 values were found in 'Narince', 'Çavuş', and 'Trakya İlkeren' cultivars (– 11.0 °C, – 12.1 °C, and – 16.1 °C, respectively). While phloem viability rate was 77.3% in 'Çeliksu', it was determined as 8.0% in the 'Çavuş' cultivar. The highest primary, secondary, and tertiary bud viability was determined in the 'Karaerik' cultivar (64.7%, 67.3%, and 68.0%, respectively). On the other hand, the least bud viability rates were obtained in 'Çavuş', 'Narince', and 'Trakya İlkeren' cultivars. In the growing room condition, the highest mean bud burst (60.7%), bud sprouting ratio (61.0%), and cluster number per shoot (0.42 cluster) were obtained in the 'Çeliksu' cultivar in growing room condition. The highest mean shoot length (4.8 cm), rooting ratio (59.3%), root length (4.10 cm), and root scale (1.19) were determined in the 'Karaerik' cultivar among freeze applied cuttings. [ABSTRACT FROM AUTHOR]

Plant diseases and pests reduce crop yields, accounting for global crop losses of 30% to 50%. In conventional agricultural production systems, these losses are typically controlled by applying chemical pesticides. However, public pressure is mounting to curtail agrochemical use. In this context, employing beneficial endophytic microorganisms is an increasingly attractive alternative to the use of conventional chemical pesticides in agriculture. A multitude of fungal endophytes are naturally present in plants, producing enzymes, small peptides, and secondary metabolites due to their bioactivity, which can protect hosts from pathogens, pests, and abiotic stresses. The use of beneficial endophytic microorganisms in agriculture is an increasingly attractive alternative to conventional pesticides. The aim of this study was to characterize fungal endophytes isolated from apparently healthy, feral wine grapes in eastern Canada that have grown without agrochemical inputs for decades. Host plants ranged from unknown seedlings to long-lost cultivars not widely propagated since the 1800s. HPLC-MS was used to identify unique endophyte-derived chemical compounds in the host plants, while dual-culture competition assays showed a range in endophytes' ability to suppress the mycelial growth of Botrytis, which is typically controlled in viticulture with pesticides. Twelve of the most promising fungal endophytes isolated were identified using multilocus sequencing and morphology, while DNA barcoding was employed to identify some of their host vines. These fungal endophyte isolates, which consisted of both known and putative novel strains, belonged to seven genera in six families and five orders of Ascomycota. Exploring the fungal endophytes in these specimens may yield clues to the vines' survival and lead to the discovery of novel biocontrol agents. [ABSTRACT FROM AUTHOR]

The prolonged drought in the Western Cape province of South Africa in recent years has been particularly detrimental to the wine industry. Water restrictions imposed by authorities and the limited supply of fresh water that can be stored, have emphasisedthe need for alternative water sources for vineyard irrigation. Treated municipal wastewater has been used successfully as an alternative source of irrigation water in other countries. A long-term trial was conducted in commercial vineyards in the Coastal region of South Africa to assess the impact of treated municipal wastewater irrigation on vineyards.  Cabernet Sauvignon and Sauvignon blanc grapevines were irrigated using treated municipal wastewater from the Potsdam wastewater treatment works for 11 years. Grapevines were either rainfed (RF), irrigated with treated municipal wastewater via a single dripper line (SLD), or received twice the volume of wastewater via a double dripper line (DLD).  Irrigation using treated municipal wastewater increased soil pH(KCl), the electrical conductivity of the saturated extract (ECe) and Cl-. Substantial amounts of Na+ and K+ accumulated in the topsoil due to irrigation with treated municipal wastewater.  These soil K+ increases could have a negative effect on wine colour stability should the levels of soil K+ be such that they are absorbed excessively by grapevines. The near-saturation hydraulic conductivity (Kns) at the surface of the soil could be related to the ECe in the topsoil. The results represent specific in-field situations in three commercial vineyards under one set of climatic conditions. [ABSTRACT FROM AUTHOR]

Abstract Comparative measurements of four Vitis vinifera cultivars were undertaken to assess assimilation tolerance to the high growth temperatures currently pervading Australian and other wine growing regions. The cultivars, cvs. Chardonnay, Merlot, Semillon, and Shiraz, were all grown in common growth conditions, and an hypothesis promulgated genotypic variation in assimilation and in the leaf temperature dependency. Assimilation responses to varying light intensity and to varying chloroplast CO2 at a range of leaf temperatures (15–45°C) were measured in leaves of each cultivar in mid‐summer. Light response curves revealed marked genotype differences in maximum assimilation, but temperature effects also varied. Semillon leaves were most sensitive to temperature, with marked and steep differences in assimilation at different temperatures while Chardonnay and Merlot were least sensitive, with relatively flat responses. There were also marked cultivar differences in response to CO2 and significant effects of leaf temperature. CO2‐saturated assimilation varied markedly, with Semillon and Merlot leaves most responsive to temperature, although there were differences in optimum temperatures and maximum rates. Chardonnay leaves remained least tolerant, with lowest rates of assimilation across most temperatures. Assimilation at 45°C also separated the cultivars and two cultivars had higher rates than at 15°C while Chardonnay and Merlot leaves had higher rates at 15°C. There were no cultivar differences in the temperature dependency of Ribulose 1,5‐bisphosphate (RuBP) carboxylation, but Semillon had a much steeper temperature dependency on RuBP regeneration than the other cultivars. All these responses confirmed the hypothesis and concluded the high‐temperature tolerance of Semillon and Shiraz and the poor adaptability of Chardonnay and possibly Merlot to perform in the current high‐temperature growth conditions.

The present work aimed to evaluate green-nano manganese produced at the Microbial Biotechnology Department, National Research Centre, Egypt, and assess its impact on the growth, yield, and fruit properties of grapevines. To this end, two experiments were conducted. The first was microbiological, where several incorporation strategies were utilized to enrich the yeast with manganese, as follows: (1) manganese was added to the liquid medium (non-growth phase), and (2) manganese was added after 24 h of incubation (growth phase). The results showed that the non-growth phase had a reduced possibility of medium contamination. The manganese concentration in the yeast cells was increased due to manganese sulfate in the medium. The manganese incorporation in yeast cells was 99.93% (1.205 × 105) higher than that of the medium at 0.0195 g/L of manganese. Although the concentration of manganese in the medium raised the optical density (OD) of the yeast cell biomass, manganese sulfate had no passive influence on it. The second experiment was horticultural, where Flame Seedless grapevines were sprayed with frozen and active fresh yeast enriched with manganese that resulted from the microbiological experiment. Grapevines were sprayed twice a year at 10 or 20 cm3/L, and the results were compared with those for the mineral and chelate forms. The results demonstrated that yeast extracts in both forms showed positive effects on grapevine. The most effective treatment with regard to growth, yield, and fruit properties was frozen yeast enriched with manganese at 20 cm3/L, which yielded 10.14 and 12.6 kg/vine, compared with the control, which recorded 3.7 and 5.6 kg/vine in the two seasons, respectively.

The economically important plant pathogen Xylella fastidiosa has been reported in multiple regions of the globe during the last two decades, threatening a growing list of plants. Particularly, X. fastidiosa subspecies fastidiosa causes Pierce's disease (PD) of grapevines, which is a problem in the USA, Spain, and Taiwan. In this work, we studied PD-causing subsp. fastidiosa populations and compared the genome sequences of 33 isolates found in Central Taiwan with 171 isolates from the USA and two from Spain. Phylogenetic relationships, haplotype networks, and genetic diversity analyses confirmed that subsp. fastidiosa was recently introduced into Taiwan from the Southeast USA (i.e. the PD-I lineage). Recent core-genome recombination events were detected among introduced subsp. fastidiosa isolates in Taiwan and contributed to the development of genetic diversity. The genetic diversity observed includes contributions through recombination from unknown donors, suggesting that higher genetic diversity exists in the region. Nevertheless, no recombination event was detected between X. fastidiosa subsp. fastidiosa and the endemic sister species Xylella taiwanensis, which is the causative agent of pear leaf scorch disease. In summary, this study improved our understanding of the genetic diversity of an important plant pathogenic bacterium after its invasion to a new region.

Precision in distributing active substances over the target area is paramount in crop protection applications. In the case of vertically-positioned crops such as grapevines, this is usually achieved with the aid of airblast technology, which can subsequently lead to increased drift. To reduce this effect, a novel distribution technique for crop protection application in the form of vertically rotating brushes has been developed. In order to investigate the influence of these two distributions on application, treatments without these supporting measures were also carried out and compared. All treatments had the same effect on the infestation by Plasmopara viticola. No increased efficiency was observed with either the airblast or rotating brush support. With regard to drift, a reduction was observed with both airblast and rotating brush treatments. The use of a standard sprayer without airblast also contributes to a significant minimization of drift.

Water stress can affect plant ecological distribution, crop growth and carbohydrate distribution, impacting berry quality. However, previous studies mainly focused on short-term water stress or osmotic stress and few studies paid attention to the responses of grape to long-term water stresses. Grapevines were subjected to no water stress (CK), mild water stress (T1) and moderate water stress (T2). Hundred-berry weight and malic acid content were reduced under T1 and T2; however, glucose and fructose content showed the opposite trend. Endogenous hormones and polyamines (PAs) can regulate plant growth and development as well as physiological metabolic processes. T1 and T2 could increase abscisic acid content, however, indole-3-acetic acid, jasmonate, gibberellins 3 and 4, cytokinin and trans -zeatin contents were slightly decreased. Three species of PAs (putrescine, spermidine and spermine) were detected, presenting obvious tissue specificity. Furthermore, there was a statistically positive correlation relating spermidine content in the pulp with glucose and fructose contents of grape berries; and a negative correlation with organic acid. In summary, water stress had a profound influence on hormonally-driven changes in physiology and berry quality, indicating that endogenous hormones and the PAs play a critical role in the development and ripening of grape berries under water stress. Grapevine (Vitis vinifera L.) is one of the most economically important fruit crops, with a high economic value worldwide. Most vine-growing areas globally are in temperate zones characterised by high temperatures and prolonged dry periods. Phytohormones and polyamines, as important endogenous signal mediators, regulate a plethora of metabolic processes and responses to water stress. Therefore, it is necessary to investigate the effects of water stress on hormones and free polyamines in various tissues. [ABSTRACT FROM AUTHOR]

The southern region of the Republic of Moldova, specifically ATU Gagauzia, offers highly favourable conditions for cultivating diverse grape varieties with multiple harvest utilization options, including wine, brandy, juices, and fresh or dried consumption. Grapevines, adaptable yet sensitive to environmental changes, were the focus of our analysis regarding meteorological fluctuations' impact on the growth of grape shoots and the development of leaf surfaces. Our research aimed to assess the changes in meteorological conditions in the ATU Gagauzia and their impact on the growth dynamics of grapevine shoots, as well as the development of leaf surfaces, yields of introduced clones of European selection. Temperature and precipitation levels significantly impacted the growth of grapevine shoots and the development of shoot leaf surfaces, vines, and vineyards. Aligning these factors with the requirements of grapevines optimizes the growth and development of the annual grapevine growth. Meteorological conditions varied across study years, benefiting grapevine growth in certain years (2017-2018) but proving less favourable in others due (2019-2020) to reduced precipitation and higher temperatures during the growing season. The research findings indicate that the growth parameters of shoots, the development of leaf surfaces, LAI, and yield of clone R5 Cabernet Sauvignon in the agroecological conditions of ATU Gagauzia depend on both the rootstock variety and the fluctuating meteorological conditions. It has been established that when grafting the investigated clone onto RxR 101-14, growth indicators, the development of annual shoot growth, leaf surface and yields were lower compared to the vines grafted onto BxR Kober 5BB. This difference was evident throughout the entire research period but was particularly pronounced during periods of adverse meteorological conditions. Specifically, in 2020, these indicators decreased by 1.1-1.2 times compared to the experimental option BxR Kober 5BB. [ABSTRACT FROM AUTHOR]

Simple Summary: A study was conducted in two vineyards located in Northern Italy to investigate the effects of mechanical leaf removal, insecticide application, and their interaction on grapevine arthropods. The results showed that the use of insecticides reduced the population densities of leafhoppers and predatory mites. Mechanical leaf removal had a greater impact on the populations of predatory mites compared to leafhoppers. Interestingly, in one of the vineyards, phytophagous mite populations increased some weeks after both leaf removal and insecticide application. These effects are discussed within the IPM framework. In this study, we tested the effects of mechanical leaf removal, insecticide application, and their interaction on leafhoppers and phytophagous and predatory mites occurring in two vineyards over three growing seasons. Leaf removal was performed in the fruit zone using a two-head pulsed air leaf remover, while insecticides were applied with a tunnel air-assisted sprayer at the maximum dose/ha recommended on the product label. Results demonstrated the efficacy of insecticide application in reducing the population densities of leafhoppers but also their detrimental effects on predatory mites. In a number of case studies, leaf removal reduced leafhopper and predatory mite densities. In one vineyard, phytophagous mite populations increased some weeks after leaf removal and insecticide application, highlighting the need to carefully consider the potential impact of vineyard management practices on non-target arthropods in the IPM framework. [ABSTRACT FROM AUTHOR]

BackgroundIntrogressive hybridization can reassort genetic variants into beneficial combinations, permitting adaptation to new ecological niches. To evaluate evolutionary patterns and dynamics that contribute to introgression, we investigate six wild Vitis species that are native to the Southwestern United States and useful for breeding grapevine (V. vinifera) rootstocks.ResultsBy creating a reference genome assembly from one wild species, V. arizonica, and by resequencing 130 accessions, we focus on identifying putatively introgressed regions (pIRs) between species. We find six species pairs with signals of introgression between them, comprising up to ~ 8% of the extant genome for some pairs. The pIRs tend to be gene poor, located in regions of high recombination and enriched for genes implicated in disease resistance functions. To assess potential pIR function, we explore SNP associations to bioclimatic variables and to bacterial levels after infection with the causative agent of Pierce's disease (Xylella fastidiosa). pIRs are enriched for SNPs associated with both climate and bacterial levels, suggesting that introgression is driven by adaptation to biotic and abiotic stressors.ConclusionsAltogether, this study yields insights into the genomic extent of introgression, potential pressures that shape adaptive introgression, and the evolutionary history of economically important wild relatives of a critical crop.

We present survey data from 436 grapevine growers across Switzerland and their production, pest, and risk management decisions. The online survey was conducted in spring 2022 in the three main official languages in Switzerland (German, French, Italian). The survey was used to obtain information on variety choice and farm management strategies, as well as farmer, farm, and spatial environmental characteristics. Moreover, we collected information around fungus-resistant grapevine varieties such as knowledge, attitudes, and perceptions of these varieties. We also elicited the current cultivation and growers’ intentions on future acreage under these varieties. In addition, data were collected on growers’ pest management strategies against weeds, insects, and fungi. Characteristics of the farm manager collected include education, farming goals, wine-related expertise, and information sources used. Information about the farm consist of marketing channels, labels, direct payment schemes, production systems and pesticide application machinery, among other details. Moreover, risk and time preferences, self-efficacy and locus of control were collected via self-assessed scales. The survey data were matched with spatial climatic data on municipality level (e.g. on temperature, precipitation, the number of yearly hail days, average sunshine duration and relative humidity) as well as pest pressure (e.g. infection risk by Oidium and Peronospora viticola) at weather station level.

Phenolic compounds are plant secondary metabolites with strong antioxidant potential. They are involved in stress tolerance, plant defense mechanism, and protection against environmental factors. Due to their medicinal and antioxidant properties, they have been part of the human diet for centuries. They also affect the overall quality of the grapes for commercial use. Fruit color is one quality attribute that is directly influenced by the production of anthocyanins in the berry skin. The production of anthocyanins is, however, linked with the production of abscisic acid. This review is focused on the production of different phenolic compounds in grapes, the role of abscisic acid in the production of anthocyanin contents through the phenylpropanoid pathway, and its effect on color development and final quality. [ABSTRACT FROM AUTHOR]

Climate change is a critical challenge for the global grape and wine industry, as it can disrupt grapevine growth, production, and wine quality. Climate change could influence the cost-effectiveness and growth of the wine industry in different wine regions since grapevine development is deeply dependent on weather (short-term) and climate (long-term) conditions. Innovation and new technologies are needed to meet the challenge. This review article addresses the impact of climate change on grapevines, such as vine phenology, pest and disease pressure, crop load, and grape and wine composition. It also reviews recent advances in the areas of viticultural manipulation and relevant technologies to potentially reduce the impact of climate change and help growers improve grape quality. Remote sensing is used for vineyard microclimate monitoring; thermal sensors combined with UAVs, aircraft, or satellites are used for water management; soil electrical conductivity sensors have been developed for soil mapping. Viticultural manipulations, such as regulated deficit irrigation for water use efficiency and berry-ripening delay for growing quality fruit, are also discussed. The review assesses future directions for further technological development, such as soil and vine water monitoring devises, precision viticulture, and artificial intelligence in vineyards. [ABSTRACT FROM AUTHOR]

Plant diseases and pests reduce crop yields, accounting for global crop losses of 30% to 50%. In conventional agricultural production systems, these losses are typically controlled by applying chemical pesticides. However, public pressure is mounting to curtail agrochemical use. In this context, employing beneficial endophytic microorganisms is an increasingly attractive alternative to the use of conventional chemical pesticides in agriculture. A multitude of fungal endophytes are naturally present in plants, producing enzymes, small peptides, and secondary metabolites due to their bioactivity, which can protect hosts from pathogens, pests, and abiotic stresses. The use of beneficial endophytic microorganisms in agriculture is an increasingly attractive alternative to conventional pesticides. The aim of this study was to characterize fungal endophytes isolated from apparently healthy, feral wine grapes in eastern Canada that have grown without agrochemical inputs for decades. Host plants ranged from unknown seedlings to long-lost cultivars not widely propagated since the 1800s. HPLC-MS was used to identify unique endophyte-derived chemical compounds in the host plants, while dual-culture competition assays showed a range in endophytes’ ability to suppress the mycelial growth of Botrytis, which is typically controlled in viticulture with pesticides. Twelve of the most promising fungal endophytes isolated were identified using multilocus sequencing and morphology, while DNA barcoding was employed to identify some of their host vines. These fungal endophyte isolates, which consisted of both known and putative novel strains, belonged to seven genera in six families and five orders of Ascomycota. Exploring the fungal endophytes in these specimens may yield clues to the vines’ survival and lead to the discovery of novel biocontrol agents.

Ethylene (ETH) plays important roles in various development programs and stress responses in plants. In grapevines, ETH increased dramatically under chilling stress and is known to positively regulate cold tolerance. However, the role of ETH in transcriptional regulation during chilling stress of grapevine leaves is still not clear. To address this gap, targeted hormone profiling and transcriptomic analysis were performed on leaves of Vitis amurensis under chilling stress with and without aminoethoxyvinylglycine (AVG, a inhibitor of ETH synthesis) treatment. APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) and WRKY transcription factors (TF) were only the two highly enriched TF families that were consistently up-regulated during chilling stress but inhibited by AVG. The comparison of leaf transcriptomes between chilling treatment and chilling with AVG allowed the identification of potential ETH-regulated genes. Potential genes that are positively regulated by ETH are enriched in solute transport, protein biosynthesis, phytohormone action, antioxidant and carbohydrate metabolism. Conversely, genes related to the synthesis and signaling of ETH, indole-3-acetic acid (IAA), abscisic acid (ABA) were up-regulated by chilling treatment but inhibited by AVG. The contents of ETH, ABA and IAA also paralleled with the transcriptome data, which suggests that the response of ABA and IAA during chilling stress may regulate by ETH signaling, and together may belong to an integrated network of hormonal signaling pathways underpinning chilling stress response in grapevine leaves. Together, these findings provide new clues for further studying the complex regulatory mechanism of ETH under low-temperature stress in plants more generally and new opportunities for breeding cold-resilient grapevines. • ETH increased dramatically under chilling stress in grape leaves. • AP2/ERFs and WRKYs TFs exhibited consistent up-regulation during cold stress. • ETH-regulated genes are enriched in biological functions (e.g. hormone, transport). • ABA and IAA may be regulated by ETH during chilling stress in grape leaves. • A network of metabolic and signaling pathways underpin grape leaf cold response. [ABSTRACT FROM AUTHOR]

• Environmental variability affects grapevine phenology, yield and fruit quality. • STICS was robust and well adaptable to table grape cultivars in new emerging viticulture regions. • Model efficiency (ME) was high for phenology (up to 0.96), yield (0.84) and pruning weight (0.90). • Model predictions may help in planning vineyard operation and selecting suitable cultivar. Plants strongly interact with their environment making phenology a sensitive indicator of climatic variability. Exploring the possibility of early prediction of phenological timings of table grape cultivars has huge socioeconomic benefits for the growers. Various statistical, mechanistic, and theoretical approaches have been used for parameterization of phenology models mainly for wine grapes. The studies on application of process-based models such as STICS (Simulateur mulTIdisciplinaire pour les Cultures Standard) particularly for table grapes and non-traditional viticulture zones are rather limited. The objective of this study was to calibrate the STICS model and evaluate its performance to simulate phenology and yield of four table grape cultivars in Pothwar- a new emerging viticulture zone of south Asia. For this, phenological timings, growth and yield responses were evaluated at two locations (Islamabad and Chakwal) for two consecutive vintages (2019 and 2020). Daily weather data, soil characteristics, genotype and crop specific data were recorded for model calibration. The results indicated a high robustness of the model for simulating table grapes phenology and yield in all cases. The model simulations indicated a satisfactory to high model efficiency (ME) of 0.69 to 0.94 with a prediction variability up to 4 days for growth stages, whereas ME for yield and pruning weight was 0.84 and 0.90, respectively. The model provided an efficient decision support tool (DST) though crucial predictions for viticulture industry. For instance, early maturity (up to 10 days), lesser yield (19–34 %) and pruning weight (19–42 %) for the warmer location (Chakwal) than for the colder Islamabad were simulated by the model with a high skill. The proximity of predicted values to observed values indicates that STICS is powerful tool for predicting vine phenology and yield, thus it provides a valuable insight in timely planning vineyards operations at key growth stages and selecting cultivars with higher yield for sustainable viticulture. [ABSTRACT FROM AUTHOR]

This experiment was conducted in private orchard located in 2021season, to study the effect of chemical and Nano--NPK fertilization for compound fertilizers (NPK) (20: 20: 20), with five concentrations are 0,80,120 chemical NPK and 6, 12 Nano-NPK kg.ha-1 and foliar with chelated Nano-zinc at three concentrations 0, 100 and 200 mg.l-1. On the quantitative characteristics of fruit growth of two cultivars of grapes cultivars Vitis vinifera L. Taifi and Kamali and studying all the interactions between the studied factors. The results can be summarized as follows: The results obtained the superiority of the Taifi cultivar in traits of number of cluster per vine, number of berries per cluster over the Kamali cultivar, while Kamali cultivar was superiority in traits of cluster weight, weight and volume of 100 berry over the Taifi cultivar. The soil application of Nano- NPK fertilization especially at concentration of 12 Kg.ha-1 achieved a significant increase in most traits of the quantitative yield. Foliar application of Nano-zinc fertilizer with 200 mg.l-1 led to a significant increase in all yield traits, except for the trait of weight of 100 berry by foliar of 100 mg.l-1 had a morally effective on this trait. The interaction treatments between all factors especially 6 or 12 Nano- NPK + 200 mg.l-1 had significant effect on all the characters with both cultivars. [ABSTRACT FROM AUTHOR]

In recent years, Colomerus vitis has caused serious economic losses due to reduced grape production in Xinjiang (northwest China). Several rootstock varieties have been reported to improve the resistance of Cabernet Sauvignon to Colomerus vitis. This study explored the influence of Cabernet Sauvignon with different rootstocks on the resistance to Colomerus vitis. In particular, Cabernet Sauvignon/Cabernet Sauvignon (CS/CS) was selected as the control, and Cabernet Sauvignon grafted with five resistant rootstocks (3309C, 1103P, 140R, SO4, and 5C) was employed as the treatment. The infestation rate and injury index of Colomerus vitis to grapevines was investigated, and insect-resistant types of grapevines with different rootstocks were determined. The resveratrol (Res) content, the gene expression of resveratrol synthase (RS), and the activities of peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and superoxide dismutase (SOD) in the leaves of each rootstock grapevine were measured. The activity of the four enzymes and the content of Res were negatively correlated with the injury index. The results revealed the ability of the rootstock to improve the resistance of grapevines to Colomerus vitis by increasing the enzyme activity or Res content. In particular, 140R, SO4, and 5C rootstocks can be employed as rootstocks of the 'Cabernet Sauvignon' grapevine with resistance to Colomerus vitis. The contents of Res and the four resistance enzymes studied here can be used as indexes to evaluate the insect resistance of rootstock–scion combinations. [ABSTRACT FROM AUTHOR]

At the end of the summer season, grapevine buds (Vitis vinifera L) grown in temperate climates enter a state of winter recess or endodormancy (ED), which is induced by the shortening of the photoperiod, and during this period, the buds accumulate sucrose. In this study, we investigated whether the shortening of the photoperiod regulates the accumulation of sucrose in the buds in the same way as it regulates its entry into the ED. Because sucrose accumulation is regulated by genes that control its transport and degradation, the effect of the SD photoperiod and the transition of buds from paradormancy (PD) to ED on the expression of sucrose transporter (VvSUTs) and invertase genes (VvINVs) was studied. To analyze the possible role of sucrose during ED development, its effect on bud swelling and sprouting was studied on dormant and nondormant buds under forced growth conditions. The results showed that the SD photoperiod upregulates the expression of the VvSUT genes and downregulates that of the VvINV genes in grapevine buds. Additionally, during the transition of buds from PD to ED, the sucrose content increased, the expression of the VvINV genes decreased, and the expression of the VvSUT genes did not change significantly. Sucrose delayed bud swelling and sprouting when applied to dormant buds but had no effect when applied to nondormant buds. Therefore, we concluded that ED development and sucrose accumulation were synchronized events induced by the SD photoperiod and that a sucrose peak marks the end of ED development in grapevine buds. [Display omitted] • Sucrose accumulation and ED are triggered by the SD photoperiod. • Sucrose accumulated in the bud during ED is supplied by the cane. • Exogenous sucrose delay bud swelling and bud sprouting. [ABSTRACT FROM AUTHOR]

To investigate the effect of sucrose, yeast and landamineZn spraying and girdling on yield and berry quality of Flame Seedless grapes. Twenty four uniformly vine was selected, as eight treatments with three replications one vine each. The study was carried out during 2019 and 2020 seasons. The experiment set up in a randomized complete block design, where, the study included The obtained results could be summarized as follows; Yield/vine and cluster weight were significantly increased due to spray either sucrose, yeast or landamineZn as well as arm girdling compared to untreated ones (control). Spraying 4 g/L landamineZn was very effective in increasing yield and cluster weight than other treatments. Moreover, all studied treatments significantly improved the berry quality in terms of increasing berry weight, total soluble solids and anthocyanin in skin of berries and decreasing berry firmness and total acidity compared to untreated ones. The greatest results were obtained due to spraying landamineZn at 2 or 4 cm3/L where gave a high yield of good berry quality. No significant differences were obtained due to spray landamineZn at 2 or 4 cm3/L, as well as yeast, sucrose or girdling. It could be concluded that spraying 2 to 4 cm3/L landamineZn to get high yield with good cluster and berry quality of Flame Seedless grapes.

In this study, we tested the effects of mechanical leaf removal, insecticide application, and their interaction on leafhoppers and phytophagous and predatory mites occurring in two vineyards over three growing seasons. Leaf removal was performed in the fruit zone using a two-head pulsed air leaf remover, while insecticides were applied with a tunnel air-assisted sprayer at the maximum dose/ha recommended on the product label. Results demonstrated the efficacy of insecticide application in reducing the population densities of leafhoppers but also their detrimental effects on predatory mites. In a number of case studies, leaf removal reduced leafhopper and predatory mite densities. In one vineyard, phytophagous mite populations increased some weeks after leaf removal and insecticide application, highlighting the need to carefully consider the potential impact of vineyard management practices on non-target arthropods in the IPM framework.

Fine‐scale climate information is critical to understand species–climate relationships. It is usually obtained by interpolating meteorological station data or by downscaling coarse‐gridded climate data. In mountain areas, however, the low station density and macroclimate variables used in coarse‐gridded climate products cannot reproduce fine‐scale variations caused by the complex topography and thus result in biased predictions of species responses to climate change. Here, we present an innovative method to estimate daily local air temperature at 100 m spatial resolution in the mountain region of South Tyrol (Central Alps, Italy), called the cloud‐corrected model. We introduce a correction factor that couples solar radiation and cloud cover data to improve air temperature predictions. Results are compared to models that either consider elevation only (lapse‐rate model) or elevation and solar radiation but not cloud cover (clear‐sky model) using a set of independent meteorological stations for validation. Moreover, all models were tested to predict critical phenological stages of the climate‐sensitive species Vitis vinifera. Over the vegetative period, the cloud‐corrected model significantly reduced the mean absolute error of predicted temperature compared with the lapse rate and clear‐sky model by 10 and 23%, respectively, and the bias by 93 and 90%, respectively. Solar radiation and cloud cover both strongly influenced local air temperature and their inclusion in temperature estimates greatly reduced systematic biases and improved predictions of important plant phenological stages by multiple days. Our method therefore provides a new way to include easily accessible topography and climate data into fine‐scale temperature predictions and accounts for important climate forcing factors that otherwise are often neglected. It combines efficiency and accuracy, because it limits data requirements but still operates on an ecologically relevant spatial scale. Thus, our approach offers promising opportunities to improve the understanding of species–climate relationships, especially in regions sensitive to the effects of climate change. [ABSTRACT FROM AUTHOR]

Abstract Background Introgressive hybridization can reassort genetic variants into beneficial combinations, permitting adaptation to new ecological niches. To evaluate evolutionary patterns and dynamics that contribute to introgression, we investigate six wild Vitis species that are native to the Southwestern United States and useful for breeding grapevine (V. vinifera) rootstocks. Results By creating a reference genome assembly from one wild species, V. arizonica, and by resequencing 130 accessions, we focus on identifying putatively introgressed regions (pIRs) between species. We find six species pairs with signals of introgression between them, comprising up to ~ 8% of the extant genome for some pairs. The pIRs tend to be gene poor, located in regions of high recombination and enriched for genes implicated in disease resistance functions. To assess potential pIR function, we explore SNP associations to bioclimatic variables and to bacterial levels after infection with the causative agent of Pierce’s disease (Xylella fastidiosa). pIRs are enriched for SNPs associated with both climate and bacterial levels, suggesting that introgression is driven by adaptation to biotic and abiotic stressors. Conclusions Altogether, this study yields insights into the genomic extent of introgression, potential pressures that shape adaptive introgression, and the evolutionary history of economically important wild relatives of a critical crop.

Bacterial plant pathogens often encounter reactive oxygen species (ROS) during host invasion. In foliar bacterial pathogens, multiple regulatory proteins are involved in the sensing of oxidative stress and the activation of the expression of antioxidant genes. However, it is unclear whether xylem-limited bacteria, such as Xylella fastidiosa, experience oxidative stress during the colonization of plants. Examination of the X. fastidiosa genome uncovered only one homologue of oxidative stress regulatory proteins, OxyR. Here, a knockout mutation in the X. fastidiosa oxyR gene was constructed; the resulting strain was significantly more sensitive to hydrogen peroxide (H2 O2 ) relative to the wild-type. In addition, during early stages of grapevine infection, the survival rate was 1000-fold lower for the oxyR mutant than for the wild-type. This supports the hypothesis that grapevine xylem represents an oxidative environment and that X. fastidiosa must overcome this challenge to achieve maximal xylem colonization. Finally, the oxyR mutant exhibited reduced surface attachment and cell-cell aggregation and was defective in biofilm maturation, suggesting that ROS could be a potential environmental cue stimulating biofilm development during the early stages of host colonization.

Grapevine serves as a host for an array of pathogenic agents, among which powdery mildew (PM), a fungal disease, stands as a major threat under changing climate and erratic weather patterns. The study aimed to examine the physiological, biochemical responses and microscopic examinations of diverse grapevine genotypes including the 42 Vitis species to powdery mildew infection caused by Erysiphe necator (Schw.) Burrill. Significant reductions were observed in leaf gas exchange parameters like net photosynthetic rate (33.09 %) and transpiration rate (32.36 %) in the infected leaves of susceptible genotypes compared to resistant and moderate genotype groups. Susceptible genotypes had higher intercellular CO 2 concentration (4.01 %). Chlorophyll fluorescence analysis revealed a decrease in the maximum quantum efficiency of photosystem-II in PM-infected leaves across the genotype groups. Furthermore, PM infection led to a decrease in chlorophyll content, particularly in susceptible plants, along with a notable reduction in total chlorophyll (25.86 %) and total carotenoids (3.58 %) contents. The ascorbic acid/dehydroascorbic ascorbic acid ratio was observed to be increased by 50 % in the susceptible genotypes due to PM infection. The higher potassium content was registered in healthy leaves of resistant genotypes compared to PM infection stage. This clearly demonstrated the genotype-specific ability to withstand biotic stress. Antioxidant enzyme activities, including glutathione reductase (1.27-fold), polyphenol oxidase (1.15-fold), phenylalanine ammonia-lyase (1.02-fold) and peroxidase (1.21-fold), were enhanced in PM infected plants, suggesting the activation of different defence mechanisms against oxidative stress induced due to pathogen. Scanning electron microscopy revealed prominent differences in fungal hyphae growth between susceptible and resistant genotypes, which showed restricted tissue growth and host cell necrosis. [Display omitted] • This study elucidates the complex response of grapevine germplasm to PM infection, highlighting the genotype-specific differences in disease susceptibility and defense mechanisms. • Changes in different groups of genotypes revealed major alterations in secondary metabolites due to defence response of leaf tissue to E. necator. • Susceptible genotypes showed significant reduction in gas exchange parameters, chlorophyll fluorescence and chlorophyll content in infected leaves compared to the resistant genotypes. • Antioxidant activities were found to be enhanced in the infected plants, suggesting their role in the defence mechanisms against oxidative stress. • The AA/DHA ratio was observed to be increased by 50 % in the susceptible genotypes after PM infection resulting in altered redox state. [ABSTRACT FROM AUTHOR]

Absorbed energy in excess of that used by photosynthesis induces photoinhibition, which is common in water deficit conditions, resulting in reductions in stomatal conductance. In grapevines, controlled water deficit is a common field practice, but little is known about the impact of a given water shortage on the energy transduction processes at the leaf level in relation to contrasting stomatal sensitivities to drought. Here, we assessed the effect of a nearly similar water deficit condition on four grapevine varieties: Cabernet Sauvignon (CS) and Sauvignon Blanc (SB), which are stomatal sensitive, and Chardonnay (CH) and Carménère (CM), which are less stomatal sensitive, grown in 20 L pots outdoors. Plants were maintained to nearly 94% of field capacity (WW) and 83% field capacity (WD). We have assessed plant water status, photosynthesis (AN), photorespiration, AN vs. PAR, ACi curves, photochemical (qP) and non-photochemical (qN) fluorescence quenching vs. PAR, the photoprotective effectiveness of NPQ (qPd) and light interception by leaves. Photorespiration is important under WD, but to a different extent between varieties. This is related to stomatal sensitivity, maintaining a safe proportion of PSII reaction centres in an open state. Additionally, the capacity for carboxylation is affected by WD, but to a greater extent in more sensitive varieties. As for qN, in WD it saturates at 750 μmol PAR m−2s−1, irrespective of the variety, which coincides with PAR, from which qN photoprotective effectiveness declines, and qP is reduced to risky thresholds. Additionally, that same PAR intensity is intercepted by WD leaves from highly stomatal-sensitive varieties, likely due to a modification of the leaf angle in those plants. Pigments associated with qN, as well as chlorophylls, do not seem to be a relevant physiological target for acclimation. [ABSTRACT FROM AUTHOR]

Featured Application: This work provides a reference support to further test the hypothesis that Vitis vinifera cultivars with wide xylem vessels may be more susceptible to esca disease and opens the way to alternative cultural practices and disease management strategies. Esca disease is one of the most important grapevine trunk diseases. It seriously reduces the quality and quantity of grapevine production, and results in a shorter vineyard lifespan. Previous studies have suggested that wide xylem vessel diameter favours development on grapevine of Phaeomoniella chlamydospora, one of the fungi involved in esca, thus affecting disease susceptibility. In this study, cultivars mainly originated from European countries, 27 white-berried and 24 red-berried grapevine cultivars, were grown in the same experimental vineyard and were analysed for xylem vessel sizes (as diameter and frequency) for correlation with esca incidence. In this study, the cultivars showed significant differences in the xylem vessel parameters. However, no relationship was detected between vessel size and esca incidence in the field. Overall, white-berried cultivars showed wider vessel diameters than red-berried cultivars. The relationship between xylem vessel size in the red-berried and white-berried cultivars and incidence of esca symptoms is discussed. We suggest that vessel anatomy profiles can provide useful information for further investigations on grapevine genotype structure–esca incidence relationships. [ABSTRACT FROM AUTHOR]

The lack of winter cold is a severe limitation for the cultivation of grapevines (Vitis vinifera L) in areas with warm winter climates. This phenomenon is currently becoming quite important due to global warming, which will increase winter temperatures in many temperate regions of the planet where grapevines are cultivated. Although various physical and chemical stimuli have been used to address the lack of winter cold in grapevine cultivation, quantitative studies on its effects on different cultivars are limited. Here, the effects of (a) low temperatures during endodormancy (ED), (b) temperature increases during eco-dormancy (ECD) and (c) the effects of dormancy-breaking compounds such as hydrogen cyanamide (HC) and sodium azide (AZ) on the budburst of an early budbreak cultivar, Chardonnay, and an late budbreak cultivar, Thompson seedless, were assessed. The results were analysed by the Kaplan–Meier method, and the log-rank test was used to establish statistical significance between the control and treatments. In general, Chardonnay grapevines were more sensitive than Thompson seedless grapevines to all budbreak stimuli, and a temperature increase during ECD was the stimulus that had the greatest effect on the budbreak in both cultivars. Exposure to cold temperatures during ED increased the cold hardiness and improved the budbreak in both cultivars. Based on the results, a relationship between the degree of bud cold hardiness and budbreak potential is suggested, and it is proposed that the greater the cold hardiness achieved by the buds, the better their subsequent budbreak will be. [ABSTRACT FROM AUTHOR]

In order to address the problems of low efficiency and low degree of mechanization of artificial soil clearing of the grapevines in spring in Xinjiang grape growing regions, a grapevine cold-proof soil clearing machine was designed. The machine is mainly composed of a frame, gearbox, suspension device, soil clearing parts, hydraulic system and mechanical transmission system, etc. The motion track of the soil clearing parts was analyzed to obtain the key factors affecting the performance of the grapevine cold-proof soil clearing machine that were determined. The three-factor, three-level quadratic regression orthogonal experiment was carried out with the forward speed, soil clearing parts' diameter and rotation rate of soil clearing parts as factors and the soil clearing distance was used as evaluation index. The results showed that the order of influence on the soil clearing distance was rotation rate of soil clearing parts > forward speed> soil clearing parts diameter. The parameters were optimized based on response surface method with the following results: the rotation rate of soil clearing parts speed was 277.7 r/min, the forward speed was 3.5 km/h, and the soil clearing parts diameter was 681.7 mm. The validation experiment was carried out with the optimal parameters' combination. The soil clearing distance was 85.44 cm, which was consistent with the predicted results of the model. This research results can provide reference for the development of other types of grapevine soil clearing machine. [ABSTRACT FROM AUTHOR]

Wine is the most important product from the Douro Region, in Portugal. Ampelographs are disappearing, and farmers need new solutions to identify grapevine varieties to ensure high-quality standards. The development of methodology capable of automatically identify grapevine are in need. In the scenario, deep learning based methods are emerging as the state-of-art in grapevines classification tasks. In previous work, we verify the deep learning models would benefit from focus classification patches in leaves images areas. Deep learning segmentation methods can be used to find grapevine leaves areas. This paper presents a methodology to segment grapevines images automatically based on the U-net model. A private dataset was used, composed of 733 grapevines images frames extracted from 236 videos collected in a natural environment. The trained model obtained a Dice of 95.6% and an Intersection over Union of 91.6%, results that fully satisfy the need of localise grapevine leaves. [ABSTRACT FROM AUTHOR]

The study aimed to improve the micrografting technique for rapid in vitro grapevine plantlet propagation using Flame Seedless scion and Freedom as rootstock. Explants obtained in vitro were cultured in MS media containing 0.4 mg L-1 BAP. For micrografting, six methods were used: sterile wire ties, sterile metal needle, wax, aluminum foil, gel, and callus. Data was collected on morphological and biochemical parameters in micrografts produced using various procedures. With various degrees of success, all in vitro micrografting procedures successfully produced grafts. The best results of morphological parameters were recorded in micrografting by wax method with the highest survival (83.88%), number of shoots/explants (1.77), shoot length (1.66 cm), leaves/shoot (4.55), rooting (58.20 %), root length (1.27 cm). In contrast, the callus method had the least value for these parameters. Wax and aluminum foil methods were found to be a promising alternative to traditional grapevine propagation methods in the study. [ABSTRACT FROM AUTHOR]

Coloured sticky card traps are widely used for sampling and control of sap-sucking insect pests. In European vineyards they are used for monitoring leafhoppers [i.e., Empoasca vitis (Gothe), Zygina rhamni Ferrari, Scaphoideus titanus Ball], the vine thrips Drepanothrips reuteri Uzel and the leafhopper egg parasitoid Anagrus atomus (L.). A study was conducted to establish the trap factors that influence captures of these insects (i.e., size, inclination, exposure days, colour, position within canopy and side orientation). The total captures of grapevine leafhoppers increased as trap size increased, without a significant decline in captures relative to unit area. All leafhopper species were more attracted by vertical traps than horizontal traps, and in the latter case, E. vitis and Z. rhamni were mainly captured on the underside of the trap, while S. titanus on the upper side. For all leafhoppers and D. reuteri, efficiency decreased with the number of days the traps remained in the field. Yellow was a colour preferred by all insects, with Z. rhamni showing a strong preference for lighter yellows. S. titanus was also captured by red traps and A. atomus by colourless ones. Z. rhamni and S. titanus showed a preference for traps placed in shady positions, whereas E. vitis and D. reuteri preferred traps in sunny positions. E. vitis and D. reuteri preferred trap sides exposed to sunlight in the late afternoon and early morning, respectively. Our results were compared with the literature and discussed in relation to the feeding preference and behaviour of the different species. [ABSTRACT FROM AUTHOR]

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present investigation was carried out during 2019 and 2020 seasons to study the effect of GA3 and some natural plant compounds on growth and fruiting of Thompson Seedless grapevines. The experiment was arranged in a randomized complete block design in which the study involved six treatments with three replications, one vine each. Pruning wood weight, leaf area and total leaf chlorophyll were significantly increased by spraying either GA3, humic acid, selenium, turmeric or roselle extracts compared to water sprayed ones (control). Spraying humic acid, turmeric or selenium were very effective on improving vegetative growth, yield/vine, and cluster traits. Moreover, these treatments significantly improved the berry quality in terms of increasing the berry weight, total soluble solids, reducing sugars of berries compared to unsprayed ones. The best results were obtained on the vines that sprayed with 0.1% humic acid or turmeric extract. No significant differences were obtained among humic acid turmeric or selenium spraying. It could be concluded that spraying humic turmeric or selenium at 0.1% three times annually was necessary to get high yield with good cluster and berry quality of Thompson Seedless grapevines. Moreover, such treatments more effective to overcome the adverse effect of using GA3 i.e. delay the berry ripening and reducing full coloration of colored cultivars. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organically produced conventional products have gained great attention in accordance with the increasing awareness on healthy foods as well as improvements in living standards. Environment friendly strategies to extend the quality of grapes after commercial maturity provide healthy and profitable sustainability in market chain. In the present study, possibilities to maintain the quality of grape clusters on grapevines without any chemical treatments have been studied under vineyard conditions in temperate climate characteristics of Konya Province in Central Anatolia. Grape clusters of 'Alphonse Lavallée' and 'Narince', one of the most popular conventional grape cultivar in Turkey, were kept on the vines trained with bilateral cordon system. The vines were drip irrigated during the hot summer and the vine canopy was covered with black nets after veraison to protect from the birds, hail and climatic extremities. After commercial maturity, twelve cluster samples per cultivar were collected with monthly intervals to investigate the changes in quality. Up to the 3rd sampling date (at the end of November 2019), little losses in quality features were determined in both cultivars. At the end of the study, at 4th moth (December), significant decay incidences were observed with similar patterns in cultivars. General findings demonstrated that the grape clusters could be maintained on grapevines under intact condition of the cool autumn season in temperate zone by protecting them from the external damages using convenient protective materials up to three or four months depending on the response of cultivars to environmental variables. [ABSTRACT FROM AUTHOR]

This endeavor includes thirty grapes' genotypes grown in northern zones of Punjab, Pakistan to determine similarities and dissimilarities in forty-four morphological traits according to the descriptor "International Plant Genetic Resources Institute (IPGRI)". The relation between the genotypes was determined by principal component analysis (PCA), and similarity was worked out by using cluster analysis. The dendrogram divided the genotypes into two main groups with classes and subclasses. The variation present within the class was up to 81.72% while the difference between classes was 18.28%. The morphological quantitative traits such as bunch length, bunch width, bunch weight, peduncle length, the weight of 10 berries, number of berry in a bunch, berry length, and berry width were in the following range 27.50-11 cm, 13.75-5 cm, 583.56-77.70 g, 6.50-1.55 cm, 53.70-9.70 g, 354-28, 27.37-11.40 mm and 18.06-10.41 mm respectively, which indicated a wide level of diversity in the selected genotypes. Based on phenological attributes, "Regina", "Perlet", and "Early White" were found early maturing genotypes to prevent berry rotting due to monsoon rains at the final stage of ripening. The data generated in this study would be helpful to preserve the existing germplasm and be available for designing future breeding programs. [ABSTRACT FROM AUTHOR]

Yellows diseases in grapevine, associated with the presence of different phytoplasmas, are a major problem for growers, with no environmentally friendly means of control. Frateuria defendens (Frd), a bacterium with endophytic traits, has been shown to reduce yellows symptoms in grapevine plantlets under laboratory conditions. The objective of this study was to test whether similar effects could be achieved under field conditions. A trial was conducted in a heavily infected vineyard in northern Israel for two consecutive years. A suspension of Frd cells (108·mL-1) was applied bi-weekly by foliar spray on grapevines from bud burst to leaf senescence. Frd penetrated the leaves during the growing period but not during leaf senescence and could be detected in the leaves by PCR analysis up to 14 days post-spraying. The rate of yellows infection was lower in the treated grapevines compared to its increase in untreated grapevines and the yield of symptomatic plants was improved by 10 to 20 %. Taken together, the results suggest Frd acted as a biological control agent in vineyards under the experimental conditions tested. [ABSTRACT FROM AUTHOR]