Vine Yield Research Articles

Evaluation of Some Sweetpotato (Ipomoea batatas [L.] Lam) Varieties in Mozambique

In Mozambique, sweetpotato plays a significant role in rural areas, where the farmers use it to feed their families and as an income. In this study, we aimed to investigate the performance of different sweetpotato varieties in Niassa, Mozambique. The trial was set up in Malulu, Sanga district, located 60 km away from Lichinga, capital of Niassa, Mozambique. In Sanga, the rainy and hot season occurs from December to March, and the dry and cold season is from May to October. In this trial, the treatments correspond to sweetpotato varieties. We used the randomized block design with 12 sweetpotato varieties and 3 replications. The evaluated traits were as follows: weevil damage, roots commercial yield, roots non-commercial yield, total yield, and vine yield. Regarding statistical analysis, the results per trait were submitted to the Bartlett test of homogeneity of variances and Shapiro-Wilk normality test, and then the analysis of variance and means comparison using the Scott-Knott test when necessary was performed. All the statistical analysis was conducted at 5% on the R programming language. For commercial and total yield, the varieties Local, Sumaia, Olga, and Alisha presented the best results. Esther and Irene were the varieties most attacked by weevils.

Effects of retained node numbers on berry maturity and yield components of cane-pruned Sauvignon blanc

Cane pruning is used in most New Zealand Sauvignon blanc vineyards to manage yield, vine balance (relationship between vegetative growth and fruit growth) and fruit primary and secondary metabolites. The source–sink ratio (TLA/FM—total leaf area to fruit mass or ELA/FM—exposed leaf area to fruit mass), the fruit mass to pruning mass (FM/PM), the fruit mass to cane mass (FM/CM) and fruit composition provide an assessment of the vine performance and balance. The interpretation of these metrics (i.e., TLA/FM, ELA/FM, FM/PM, FM/CM) requires their comparison with known optimal ranges specific to cultivars, locations and growing conditions. More often, such context- and cultivar-specific optimal ranges do not exist, thus warranting research to investigate them. To understand the influence of retained node numbers on the vegetative and fruit development of Sauvignon blanc, grapevines were pruned across three vineyard sites (two in Marlborough—Site 1 and 2, and one in Waipara—Site 3) over two growing seasons, retaining 10, 20, 30, 40 and 50 nodes on one to four canes (each cane carrying ten nodes, with 50-node vines carrying on average 12.5 nodes on each of the four canes). The accumulation of soluble solids (TSS) generally increased at lower node numbers and vine yields, reflecting an increase in ELA/FM, with 50-node vines having the least TSS concentration at harvest. The average berry mass, titrable acidity (TA) and pH were unaffected by node numbers over the two seasons. A low source–sink ratio induced by high node numbers not only reduced the vine capacity to ripen the current crop but also reduced the following season’s bunch number per shoot (from 1.8 to 1.6 bunches per shoot; p < 0.05), average bunch mass (from 82.0 ± 6 g to 67.7 ± 3 g; p < 0.01) and bunch mass per shoot (from 153.5 ± 15 g to 106.7 ± 9 g; p < 0.05). When compared to 50-node vines, 10-node vines had a two-fold increase in the average cane mass (from 30.1 ± 3.9 g to 69.2 ± 8.7 g; p < 0.001) and average old cane mass (from 82.4 ± 6.9 g to 163.8 ± 21 g; p < 0.001). The ELA/FM and TLA/FM required for optimal TSS accumulation were 0.75 m2 kg-1 and 2.0 m2 kg-1, respectively, across all sites. A source–sink ratio above these values resulted in high average cane mass and average old cane mass (an indication of excess vigour), while lower values indicated reduced vigour and slowed TSS accumulation. This research provides useful optimal ranges to compare and interpret vine balance metrics measured at those sites.

ANALYSIS OF SWEET POTATO PRODUCTION IN EBONYI STATE, NIGERIA

This paper analyzed sweet potato production in Ebonyi State, Nigeria. Multi-stage and proportionate sampling methods were used to collect two hundred and one sweet potato farmers for the study. Data were collected using structured questionnaire and analyzed using descriptive such as frequency and percentages and inferential statistics such as Ordinary Least Square regression model. Results showed that 74.13% of the sweet potato farmers were female with mean age of 38years, mean educational level of 12years with 96.52% of them were married having a mean household size of 8persons. Farm size, quantity of improved sweet potato varieties planted, labour and weeding were significant at 1% and 5% respectively and were positively related to vine yield while farm size, quantity of improved sweet potato varieties planted, fertilizer application and insecticide were significant at 1% and 5% respectively and were positively related to root yield. The production of sweet potato in Ebonyi state was affected by some production factors which causes low yield in the vine and root of sweet potato. Therefore, Organization of field days and farmers’ training on sweet potato production as well as procurement and distribution of improved varieties to farmers are effective strategies for stimulating adoption of the technologies.

Post-Frost Pruning Does Not Impact Vine Yield and Berry Composition in Young Grapevines

Spring frost is a perennial and widespread problem across many cool climatic and high-elevation winegrowing regions of the world. Vitis vinifera L. cv. Pinot noir is an early budding cultivar; thus, it is particularly susceptible to late-spring frost damage. In late April 2022, an advective frost event occurred throughout Western Oregon winegrowing regions and subsequently damaged a substantial number of commercial vineyards. Growers often are unsure of how to manage grapevines after a frost event. Limited research has shown little-to-no effect of pruning vs. non-pruning strategies on vine yield and productivity. In addition, pruning a frost-affected vineyard incurs additional labor costs that may offset the cost–benefit balance for the grower. Therefore, in this experiment, the effect of two different post-frost pruning treatments (cane pruning and spur pruning) on vine yield, berry composition, and vine vegetative growth were tested. No effect of post-frost pruning treatments on vine yield, berry composition, and vine vegetative characteristics was observed. Cluster numbers, cluster weights, and berries per cluster only differed between cane- vs. spur-pruned vines. Therefore, leaving frost-affected vines alone and a scaled-back vineyard management practice could be practical for economic reasons.

Investigating the Performance of Different Varieties of Cucumber under Prayagraj Agro-Climatic Condition

Nine cucumber varieties were evaluated at the vegetable research farm Department of Horticulture SHUATS, Prayagraj in randomized block design with three replications during rainy seson September -2022 for growth, yield and fruit qualities. The experimental design was Randomized Block Design consisting of nine treatment with three replications, with a view to evaluate different cultivars of cucumber viz. KH10 GREEN LONG(T1), F999(T2), C4F9(T3), SS95(T4), CUCUMBER GREEN WONDER(T5), BH05(T6), PRIYA BARSATI(T7), ANUPRIYA(T8), GREEN 4 BARSATI(T9). Cucumber Green Wonder gave maximum mean value for fruits per plant (5.20 kg) , fruit weight (174.33 g), fruit yield per plot (39.33 kg), number of node per vine (15.33) yield (42 q) , number of male flower per plant (65.00) , number at which first female flower (5.33) was observed in same varieties , maximum numbers of male flowers per plant in variety Cucumber Green Wonder (65.00) maximum length has been found in Cucumber Green Wonder (151.67) Minimum days were recorded for first Appearance of male flower in KH 10 Green Long (51.67). The variety Green 4 Barsati has taken minimum (48.00) days to first harvesting followed by F999 (53.00). cucumber green wonder was found superior based on overall performance in terms of growth, yield, quality & Economic returns. The highest cost benefit ratio was found for cucumber variety Cucumber Green Wonder under PrayagrajAgroclimate condition.

Effects of foliar applications of a proline-rich specific yeast derivative on physiological and productive performances of field-grown grapevines (Vitis vinifera L.)

The occurrence of heat waves in vineyards can damage the integrity of photosynthetic systems, impair yield and affect fruit quality. The frequency of these events is increasing due to global warming, and this is the subject of growing concern among the players in the wine sector. Canopy applications of specific yeast derivatives (SYD) are proposed to enhance plant physiology under abiotic stresses and preserve yield and fruit composition. This study aimed at assessing the effects of foliar application of a proline-rich SYD formulate, LalVigne ProHydro™ (LPH), on field-grown vines cv. Barbera. In a two-year experiment, vines subjected to multiple LPH foliar applications were compared to untreated vines (C). Gas exchange rates and vegetative and productive performances were monitored together with leaf proline, carotenoids and H2O2 concentrations. The data demonstrate that the formulate improved midday leaf water potential (+0.14 MPa), stomatal conductance (+0.15 mol m−2 s−1) and assimilation rates (+2.8 μmol m−2 s−1) under summer stress conditions. Interestingly, LPH leaves showed a dramatically higher concentration of proline (+600 %) and a significantly lower H2O2 content (-26 %) as compared to C leaves. The data suggest that this could be related to a priming effect of LPH application. Moreover, in SYD vines, cluster sunburn occurrence was reduced by 69 %, compared to C vines. At harvest, LPH improved vine yield (+1.27 kg), and LPH grapes had a significantly lower sugar concentration (-2.09 °Brix). The study demonstrates for the first time the potential benefits of proline-rich SYD application in vineyards subjected to multiple summer stress. Further studies should focus on the treatment effects on proline biosynthesis and gene expression.

Comparing defoliation and canopy sprays to delay ripening of Sauvignon blanc grapes

Higher temperatures caused by climate change are responsible for early maturation process which is often linked to low quality of grapes and wines. In this study, different canopy management techniques were tested and compared over three consecutive years (2017–19) with the aim to evaluate their capacity to delay ripening of Sauvignon blanc/SO4 grapes. These included a defoliation performed at veraison and the applications of antitranspirant (containing pinolene), kaolin and chitosan at bunch closure and veraison. The effects of the treatments on grapevine leaf gas exchanges, chlorophyll content and overall water status were measured during the three vegetative seasons. Moreover, soluble solids content and titratable acidity of berries were monitored from veraison until harvest, when final yield and berry composition were assessed. Pinolene transiently reduced the carbon assimilation rate and, independently from the growing season, significantly reduced sugar concentration in berries at harvest by -1.5°Brix as compared to the control. The defoliation reduced vine yield by 10–15 %, without significantly affecting total sugar and acid concentrations at harvest when compared to control. Kaolin and chitosan increased significantly berry acidity at harvest as compared to other treatments (i.e. defoliation and pinolene), but not to control. Under the temperate and rainy growing conditions of northeastern Italy, the antitranspirant product proved its potential as ripening retardant on a white grapevine cultivar. The high frequency of the rainfall events during the considered seasons partially hindered the full potential efficacy of the considered products sprayed to the canopy, questioning their overall efficacy under such conditions and mode of application.

Berry shattering phenomena in vineyards: The influence of maximum temperatures during flowering period in an extreme year

Phenological stages, vine yield, and quality of grapes are increasingly affected by extreme temperature conditions caused by climate change. This study aimed to investigate the impact of high temperatures over 40 °C at the flowering period of cv. Sultana Seedless (Vitis vinifera L.) vineyards on the berry shattering problem. A total of 79 vineyards were examined in the western region of Türkiye, and a level of berry shattering (0–4) was defined rapidly to determine the extent of the damage caused by high temperatures. When the two years were compared, it was found that the flowering period was eight days shorter in the first year due to the high temperatures. The study found that the berry shattering problem was more severe in the first year than in the following year among vineyards in Saruhanli, Yunusemre, and Ahmetli locations. High temperatures during the flowering period in the 2020 growing season had a more significant impact on vine yield, resulting in more berry-shattering problems compared to the second year. However, the overall number and weight of clusters increased by between 15.15%-39.52% and 20.51%-42.49% in all locations respectively, under seasonal norms in the following year. Two-year analyzes made in the same vineyards revealed that high temperatures during the flowering period are more effective than the subsequent year, affect the yield of the vines, and more berry shattering problems occur. This study also recommended that the maximum temperatures be examined during specific days and hours during the flowering period, as well as the duration of exposure. Temperatures above seasonal norms can decrease yield and cause berry shattering.

Effects of soil water-holding capacity and soil N-NO<SUB>3</SUB><SUP>−</SUP> and K on the nutrient content, vigour and yield of cv. Tempranillo vine and the composition of its must and wine

The aim of this study was to assess the relationships between the soil water-holding capacity (SWHC), nitrate nitrogen (N-NO3−) and extractable potassium (K) content of soil; the vine nutrient content, vigour and yield; and the quality of the musts and wines in DOCa Rioja vineyards over a five-year period (2010–2014). The SWHC, N-NO3− and extractable K content of the soil were analysed in twelve cv. Tempranillo (Vitis vinifera L.) plots. Vine yield, nutritional parameters and the K and polyphenol compounds in the musts and wines were determined. In general, both the SWHC and the soil N-NO3− content were positively correlated with the N and K content of the petiole, the shoot weight and the bunch weight, but negatively correlated with the polyphenol and anthocyanin content of the musts and wines. The K extractable content was also correlated with the K content of the petiole and with the K in the musts and wines. The SWHC, the N-NO3− and the extractable K are soil parameters which have been linked to the growth and ripening of the vine plant and to the composition of the must and wine. For DOCa Rioja agroclimatic conditions, assessment of these soil parameters would enable selecting soils that support obtaining wines of better quality.

Viruses on Table Vine Varietie

In Herzegovina table grapes have been grown on smaller private areas. One of the most important factors that affect the yield and quality of vines, grapes and the profit of production are the viruses. The aim of this work is to monitor the occurrence of 4 viruses (GLRaV-1, GLRaV-3, ArMV and GFLV) on 6 table grape varieties: Prima, Black Magic, Cardinal, Demir-kapija, Victoria, Alphonse Lavallée. The research was conducted in the period from November 2019 to September 2020 on one of the larger plantations north of Mostar.Studies have shown different susceptibility of different varieties to these viruses. Of the 60 samples examined, the presence of ArMV virus was not recorded. The presence of GLRaV-1, GLRaV-3 and GFLV viruses was proven by ELISA. The variety Victoria is most susceptible to infection with the GLRaV-3 virus, in which each sample of this variety is infected. The second variety that is most susceptible is Demir kapija with 80% of infected samples, followed by Cardinal with 70% and Alfonso with 50%. The most resistant varieties according to this research are Prima with 30% of infected samples and Black Magic with 10% of infected samples.

Impact of disease severity on infected bunches upon a yield of grape variety Vranec, caused by Plasmopara viticola (Berk. & M.A. Curtis) Berl and De Toni

Impact of disease severity on infected bunches upon a yield of grape variety Vanec, caused by Plasmopara viticola (Berk. & M.A. Curtis) Berl. & De Toni., every year causes damage to the yield of vines by infection the bunches while they are still unripe. It is essential to assess the severity of Downy Mildew in vineyards to predict yield loss accurately. The software platform 'image J' was used to detect and quantify the disease severity by measuring infected berries relative to healthy tissue. Regression analysis was used as a statistical method to predict yield loss. Plasmopara viticola was monitored in 2022 to find a rational solution to build a Yield Loss Forecast Model. The results of theoretical assumptions compared with actual field situations show that Yield Loss Forecasting Model within the allowed statistical range approximately predicts the yield loss of the control variant.

Salinity Stress Effects on the Growth Yield and Quality Performance of Two Sweet Potato Varieties

The yield response of several sweet potato varieties to salinity stress has been extensively studied in the scientific literature, but no research on the Koganesengan and Beniazuma varieties has been identified. The purpose of this study was to examine the effects of various irrigation salinity levels on the growth (vine and tuber lengths, stem and tuber diameters, and number of leaves, shoots, and tubers), yield (fresh, dry, tuber, and total yields, and water use efficiencies for vine, tuber, and total yields), and quality parameters (dry matter, ash, crude fiber, starch, phenolic matter, antioxidant activity, ß-carotene, ascorbic acid, protein, saccharose, glucose, and fructose contents) of these sweet potato varieties under drip irrigation. The findings show that without a varietal difference, increasing water salinity levels increased soil salinity and decreased soil pH values. Some growth and yield parameters of “Beniazuma” were negatively affected by the salinity level, but not those of “Koganesengan”. Irrigation salinity levels only had an effect on the crude fiber content and antioxidant activity of “Koganesengan” and the ash, starch, ß-carotene, and ascorbic acid contents of “Beniazuma”. Significant variations between varieties were only seen under the control treatment for all yield parameters (except dry vine yield) and water use efficiency values. According to the calculated salinity threshold and slope values, “Beniazuma” is more sensitive to salt stress than “Koganesengan”.

Testing field adaptation strategies for delaying grape ripening and improving wine composition in a cv. Macabeo Mediterranean vineyard.

Under semiarid and warm climates, field practices for climate change adaptation have to be defined in order to modulate grape composition according to the desired wine styles. Under this context, the present study investigated several viticulture practices in cv. Macabeo for Cava production. The experiment was carried out over 3 years in a commercial vineyard located in the province of Valencia (eastern Spain). The techniques tested were (i) vine shading, (ii) double pruning (bud forcing), and (iii) the combined application of soil organic mulching and shading, all of them tested against a control. Double pruning significantly modified phenology and grape composition, improving the wine alcohol-to-acidity ratio and reducing the pH. Similar results were also achieved by shading. However, the shading strategy did not significantly affect yield, unlike double pruning, which reduced vine yield even in the year following its application. Shading alone or in combination with mulching significantly improved the vine water status, suggesting that these techniques can also be used to alleviate water stress. Particularly, we found that the effect of soil organic mulching and canopy shading on stem water potential was additive. Indeed, all the techniques tested were useful for improving wine composition for cava production, but double pruning is only recommended for premium Cava production.

Grape Heterogeneity Index: Assessment of Overall Grape Heterogeneity Using an Aggregation of Multiple Indicators

Uniform grape maturity can be sought by producers to minimise underripe and/or overripe proportions of fruit and limit any undesirable effects on wine quality. Considering that grape heterogeneity is a multifaceted phenomenon, a composite index summarising overall grape heterogeneity was developed to benefit vineyard management and harvest date decisions. A grape heterogeneity index (GHI) was constructed by aggregating the sum of absolute residuals multiplied by the range of values from measurements of total soluble solids, pH, fresh weight, total tannins, absorbance at 520 nm (red colour), 3-isobutyl-2-methoxypyrazine, and malic acid. Management of grape heterogeneity was also studied, using Cabernet Sauvignon grapes grown under four viticultural regimes (normal/low crop load, full/deficit irrigation) during the 2019/2020 and 2020/2021 seasons. Comparisons of GHI scores showed grape variability decreased throughout ripening in both vintages, then significantly increased at the harvest time point in 2020, but plateaued on sample dates nearing the harvest date in 2021. Irrigation and crop load had no effect on grape heterogeneity by the time of harvest in both vintages. Larger vine yield, leaf area index, and pruning weight significantly increased GHI score early in ripening, but no significant relationship was found at the time of harvest. Differences in the Ravaz index, normalised difference vegetation index, and soil electrical conductivity did not significantly change the GHI score.

Organic mulches as an alternative for under-vine weed management in Mediterranean irrigated vineyards: Impact on agronomic performance

One of the main challenges for organic vineyards is weed management. Weeds tend to compete for water and nutrients, and can cause large yield reductions. Traditional under-vine weed management in organic vineyards consists on mechanical cultivation along the season, which is associated to soil and young vine root damages, and to high fuel consumption. Thus, sustainable alternatives need to be found. Cover crops are becoming common in the last decades due to their multiple benefits in agroecosystems. Nevertheless, under-vine cover crop implementation in Mediterranean vineyards is limited as this competes for resources (water and nutrients), reducing the yield, vegetative development, and grape size of vines. The use of organic mulches could overcome all these problems, while benefitting vine performance. In the present work, the response of vines, soil and weeds to mulching was evaluated. An experiment was carried out in Raimat, Lleida (Catalonia, NE Spain) in a commercial vineyard from 2019 to 2021, and the following treatments applied: 1) mechanical cultivation with an in-row tiller; 2) mowing a permanent spontaneous cover with an in-row mower; 3) almond shell mulch; and 4) chopped pine wood mulch. Results showed lower weed cover along the three seasons in mulched treatments, as well as higher yield, better vine water status, and greater vegetative development from traditional measurement. The latter was confirmed by and analised with further detail with measurements acquired with a mobile terrestrial laser scanner (MTLS) based on light detection and ranging (LiDAR) sensors. Besides, petiole nutrient status was better in vines without a spontaneous living cover. Organic mulches improved vine performance and weed control, so these results allow to optimize water use efficiency in the Mediterranean basin with scarce water resources. Mulching can be considered as a useful strategy that enhances a more sustainable viticulture.

Tolerance of muscadine grape to 2,4-D choline postemergence-directed

AbstractField studies were conducted in commercial muscadine vineyards in western North Carolina in 2018 and eastern North Carolina in 2019, 2020, and 2021 to determine tolerance of younger (< 9 yr) and older (≥ 9 yr) bearing muscadine grapevines to 2,4-D directed beneath the crop postemergence (POST). Treatments included 2,4-D choline at 0, 0.53, 1.06, 1.60, and 2.13 kg ae ha−1 applied as a single treatment in May or June (spring) at immediate pre-bloom, and sequential treatments at 0.53 followed by (fb) 0.53, 1.06 fb 1.06, 1.6 fb 1.6, or 2.13 fb 2.13 kg ha−1. The first sequential treatment was applied in spring fb another application of the same amount in July (summer) at pre-veraison. No differences in injury on muscadine grapevines were observed from 2,4-D treatments. Differences among treatments were not observed for yield of younger vines. However, for older vines, a difference due to 2,4-D rate was observed in 2018, when yield was higher when 2,4-D was applied at 1.6 kg ha−1 compared with nontreated grapevines, and when 2,4-D was applied at 0.53 and 2.13 kg ha−1. A rate-by-timing interaction was observed in 2019 when yield was lower from 0.53 kg ha−1 2,4-D summer application compared with all other summer treatments but similar to the nontreated. However, no biological pattern was observed from either of these differences. No differences among treatments were observed for fruit pH, titratable acidity, or soluble solid content of either younger or older vines.

GA3 and Hand Thinning Improves Physical, Chemical Characteristics, Yield and Decrease Bunch Compactness of Sultanina Grapevines (Vitis vinifera L.)

Nowadays, the Sultanina grapevines H4 strain has become widely cultivated because of its high productivity. However, this Sultanina variety is suffering from clusters with small berries, in addition highly compacted berries, thus negatively affecting the quality of bunch berries. A field experiment was carried out during the two successive seasons on Five years old Sultanina (H4 strain) grapevines grafted onto freedom rootstock grown in a private orchard located in El-Khatatba region, Minufyia Governorate, with coordinates of 30°21′ N 30°49′ E. The investigation was designed to throw light on the effect of hand thinning at levels 0, 25%, and or 50% of cluster shoulders was removed in addition to spray with 0, 20, 30, and 40 ppm GA3 for berry sizing. In addation, the first application was the hand thinning treatment, which was used on the second and third week of May for the first and the second seasons. The second application was the berry sizing treatment, applied when the berries were at 6–7 mm diameter (on the 3rd and 4th week of May for the first and the second seasons. Results indicated that the total chlorophyll content of leaf decreases when the hand thinning levels or GA3 concentration increases, while hand thinning and GA3 treatments were higher than control only concerning pruning weight. Moreover, the results showed that the first level of hand thinning treatments recorded higher values for the cluster weight than the higher level of hand thinning treatments with all the concentrations of GA3 used for sizing. The highest value was with T2. The overperformance of T2 for the vine yield and the rest of the treatments at the lower level of hand thinning were better than those at the higher level of hand thinning. In conclusion, hand thinning at 50% level and sizing with GA3 at concentration 30 ppm reduced the cluster compactness and improved the berry weight and firmness. Therefore, it could be recommended to get the most suitable yield and quality of Sultanina grapevines.

Assessing grapevine water status using Sentinel-2 images

Grapevine water status strongly impacts vine yield and berry quality, hence the importance of a cost- and time-effective methodology to estimate it in commercial vineyards. A two-year experiment was carried out in a rainfed commercial vineyard (cv. ‘Vermentino’ grafted on ‘1103P’) to test the ability of vegetation indices (VIs) derived from Sentinel-2 (S2) multispectral imagery in estimating the stem water potential (Ψstem). The S2 VIs calculated including NIR and SWIR bands (NDMI, MSI and NMSI), performed better (R2 values of 0.66, 0.66 and 0.59, respectively) than those calculated using the bands in the VIS-NIR region (R2 values 0.47, 0.58 and 0.58 for NDVI, GNDVI and NDWI, respectively). The slope between B8a and B11 bands was also significantly affected by grapevine water status. The different weather conditions occurred during the two experimental years also allowed to observe as the S2 VIs performed better in estimating Ψstem under prolonged drought conditions. Moreover, S2 VIs were not able to detect differences in grapevine water status during the onset of water stress condition

Effects of the application of forchlorfenuron (CPPU) on the composition of verdejo grapes

The application of cytokinins such as forchlorfenuron (CPPU) has been widely used in table grape varieties to increase yield and berry size. However, the potential interest of these phytoregulators in wine grapes have been scarcely analyzed. The objective of this study has been to evaluate the influence of CPPU treatment on the agronomic performance and composition of Verdejo grapes. The trial was conducted in 2021, in the Protected Designation of Origin “Rueda” (Spain). CPPU was applied using a concentration of 15 mg/L, by spraying the bunches when the berries were 5-6 mm in diameter. The photosynthesis rates and the stem water potential, measured after the application, tended to decrease in the treated plants without modify the values ​​of vine yield and vigour. The treatment significantly affected the content of soluble solids and total polyphenols of the grape must, detecting increases of 15.4% and 7%, respectively, compared to the controls. Preliminary results suggest that the application of CPPU on the bunches could improve the quality of the Verdejo grapes. The treatment would be interesting to apply in cultivation conditions where the harvest has difficulties to reach an adequate level of maturity, such as excessive vigour or too cold climate.

Assessing the Short-Term Effects of No-Till on Crop Yield, Greenhouse Gas Emissions, and Soil C and N Pools in a Cover-Cropped, Biodynamic Mediterranean Vineyard

Background and Aims. No-till is considered a core practice of conservation and climate-smart agriculture. Nevertheless, recent evidence suggests that the benefits of this practice for climate change mitigation might be overestimated, particularly in the short term. Methods and Results. In a three-year field experiment, we investigated the environmental and agronomic performance of this practice by looking at changes in soil physical properties, C and N pools, as well as vine yield and grape quality. No-till increased stratification in the distribution of active soil C (POXC), further accentuating the already existing difference between top and subsoil. No-till also slightly reduced the daily efflux of CO2 from the soil during the rainy season, showing that these plots were less prone to lose C than tilled plots. Nonetheless, no-till did not increase total soil C stocks. This, together with the lack of differences in cumulative N2O emissions, resulted in similar global warming potential in till and no-till plots. Vine yield and grape quality remained unchanged in the no-till compared to the tilled plots. Conclusions. Even though no-till did not result in short-term climate change mitigation, results of this study suggest changes in the ecological processes leading to C accumulation and mineralization and that may result in future C sequestration. There were no deleterious effects of no-till on grape yield and quality. Significance of the Study. This study shows that reducing tillage intensity in vineyards is a feasible strategy from an agronomic standpoint.