Double Pruning Research Articles

Basis scaling and double pruning for efficient inference in network-based transfer learning

Network-based transfer learning allows the reuse of deep learning features with limited data, but the resulting models can be unnecessarily large. Although network pruning can improve inference efficiency, existing algorithms usually require fine-tuning that may not be suitable for small datasets. In this paper, using the singular value decomposition, we decompose a convolutional layer into two layers: a convolutional layer with the orthonormal basis vectors as the filters, and a “BasisScalingConv” layer which is responsible for rescaling the features and transforming them back to the original space. As the filters in each decomposed layer are linearly independent, when using the proposed basis scaling factors with the Taylor approximation of importance, pruning can be more effective and fine-tuning individual weights is unnecessary. Furthermore, as the numbers of input and output channels of the original convolutional layer remain unchanged after basis pruning, it is applicable to virtually all architectures and can be combined with existing pruning algorithms for double pruning to further increase the pruning capability. When transferring knowledge from ImageNet pre-trained models to different target domains, with less than 1% reduction in classification accuracies, we can achieve pruning ratios up to 74.6% for CIFAR-10 and 98.9% for MNIST in model parameters.

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.

Parameters of apple tree crowns depending on the crown shape and pruning time

The apple tree is a leading fruit crop in Ukraine in terms of production volumes and planting areas and is a valuable food product with a high content of vitamins. In new modern plantings, fruit producers prefer intensive cultivation technologies that ensure the maximum amount of high-quality fruit yield per unit area. The main criterion for solving this problem is the design of plantings: a narrow-row scheme for planting trees and a low-volume crown shape. The purpose of the study was to establish the influence of the pruning period of different types of crown formations on the growth and productivity of apple trees of two varieties: Fuji and Honey Crisp. The study was conducted in the conditions of the central Forest-Steppe of Ukraine (Uman National University of Horticulture). The scheme of planting was 4x1 m, M.9 rootstock, chernozem sod-podzolic soil, drip irrigation. Field, statistical, and computational-analytical methods were used in the course of the study. It was identified that the growth pattern of the examined varieties differed substantially, and crown volume, projection area, and development of the feeding area prevailed in Honey Crisp trees. However, in terms of productivity, the plantings of the Fuji variety substantially exceeded the values of the Honey Crisp variety. Forming a ballerina crown with the removal of overgrown wood in a 25 cm zone on the central trunk above the lower tier of semi-cellular branches provided an increase in the growth activity of the examined trees by 3-5%. A substantial decrease in the values of crown parameters was provided by the formation of the French axis crown – there was a decrease in the crown diameter by 44%, the crown volume – by 67%, and the crown projection area and the development of the feeding area – by 69%. Performing additional summer pruning of trees also helped to reduce growth activity by 6-11%. However, the specific productivity of plantings doubled in plantings with the formation of the French axis and by 45-50% with the introduction of double pruning of trees. It is recommended that agricultural producers investigate the terms of pruning low-volume crown forms, considering varietal characteristics, to create compacted apple stands and increase the intensification of production

Double-Pruning: preventive technique against spring frost damage

The double pruning technique on Sangiovese vines, based on pre-pruning in February and finishing in April, induced a delay of bud break, which is an approach to avoid spring frost damage. The field experiment was conducted on Sangiovese vines mechanically spur-pruned during dormancy in February and manually finished post budburst to test the potential of ‘double-pruning’ approach to prevent the spring frost damage. This technique, associated with the finishing performed when the apical shoots on the mechanically-shortened canes were about 10 cm long, allowed to keep the basal buds in a dormant phase for almost 15 days, extending the resistance period against the spring frosts, particularly important for the cultivars characterized by early bud-break. Yield reduction per vine was -22% due only to the incidence of unsprouted buds, while the grape ripening profile was delayed with an increase of acidity and phenols and a decrease of pH and soluble solids.

Rootstock affects stress relieving enzymatic activity during bud break in 'Red Globe' grapevine under semi-arid condition

The role of stress relieving enzymes during bud sprouting in grapevines has already been established in different varieties. However, data on 'Red Globe' variety under tropical conditions are not reported. The present study was conducted to generate data on stress relieving enzymatic activities during bud sprout in 'Red Globe' on different rootstocks under arid conditions of India. Influence of different rootstocks on stress relieving enzymes (catalase, peroxidase, ascorbic acid oxidase and polyphenol oxidase) involved in bud sprouting under tropical conditions with double pruning and single cropping pattern was evidenced. Positive interactions were observed between enzymatic activities of stress relieving enzymes, increased bud break (64.25 %) and reduction in days taken to bud sprout (8.43 days). Among the rootstocks under study, vines on 110R and own rooted vines have strong impact on stress relieving enzymes that resulted into early and increased bud sprouting. Also, the dynamics of enzymatic activity can be used as biological indicators for forecasting the end of bud dormancy and recommencement of growth.

Characterization of Brazilian Syrah winter wines at bottling and after ageing

ABSTRACT: Double pruning extended the harvest season of wine grape (Vitis vinifera L.) to dry winter, enabling production of high quality wines in the southeastern Brazil. Winter harvest allows grapes to fulfill not only technological maturation, but also phenolic ripeness. Winter wines from Syrah grapes harvested from eight vineyards in southeastern Brazil during three harvests were analyzed for their chemical and aromatic composition after bottling and after ageing for 20, 30, and 42 months in bottle. Winter wines have high content of total phenolic compounds, which remained almost constant through ageing, as well as color intensity. Malvidin 3-O-glucoside stood out among anthocyanins, remaining 5-10 % after 39 months of ageing. Moreover, malvidin 3-O-glucoside-pyruvic acid was the main pyranoanthocyanin identified in winter wine. Polymerized pigments index ranged from 54 % at bottling to 80 % after 42 months of ageing. Young winter wines are rich in ester and monoterpene, as well as alcoholic volatile compounds responsible for ethereal, fruity, flowery, fresh and sweet aromas. Aged winter wines showed higher contents of furfural, geranyl ethyl ether, isoamyl decanoate, α-muurolene and α-calacorene, contributing to sweet, fruity and woody aromas. Syrah winter wines are characterized by high content of phenolic compounds and color stability, and keep good sensorial characteristics after ageing in bottle.

Yield and quality enhancement as influenced by pre-harvest nutrient spray in grapes (Vitis vinifera L.) var. Muscat Hamburg by adopting double pruning and double cropping system under Cumbum Valley condition

Yield and quality enhancement as influenced by pre-harvest nutrient spray in grapes (Vitis vinifera L.) var. Muscat Hamburg by adopting double pruning and double cropping system under Cumbum Valley condition

Effect of pruning strategy on 'Syrah' bud necrosis and fruitfulness in Brazilian subtropical Southeast

The change of wine grape harvest from wet season (summer) to dry season (winter) by changing the pruning management has improved quality of wines produced in the Brazilian Southeast. However, the vines need to be spur pruned twice a year, i.e. with a 1st pruning in August (winter pruning) for a vegetative cycle during the hot and wet summer, and a 2nd pruning in January (summer pruning) for a productive cycle during the cold and dry season. This double pruning strategy is made necessary by the fact that latent buds developed during the dry season cycle are not fruitful to support a productive cycle in the following year. This histological study, performed in the South of Minas Gerais State (Brazil), showed that annual single pruning done in the wet season (in January) displayed a high rate of necrosis on primary and secondary buds (bud necrosis – BN). In April, 99 days after summer pruning (DASP), the rates of BN were 40 % and 50 % at basal and apical node positions, respectively, reaching 80 % of BN in December (322 DASP). As a consequence of BN, bud potential fertility was drastically reduced from 0.5 inflorescence primordial (IP) per bud (in July) to 0.06 (in December) and bud burst in the next cycle from secondary and tertiary bud axes. Vines managed by double pruning system (submitted to summer and winter pruning) displayed a much higher fruitfulness potential, i.e. 1.46 IP per bud in December (112 days after winter pruning) and limited BN occurrence (20 %). On single pruned vines, we also observed a significant decrease of starch content in canes, trunks and roots. Internal bud anatomy showed that a random cell breakdown started 70 days DASP. At 211 DASP, all buds showed a large starch granule concentration, raphides and crystals of calcium oxalate inside idioblasts of leaf primordia and also in cortical parenchyma of the vegetative axis. The bud starch content was increased and a positive correlation between necrosis and starch accumulation was observed. The impact of carbohydrate availability on bud necrosis development was discussed. This study showed that the necrosis development towards secondary and tertiary axis of the dry season buds is the main reason of unfruitfulness in the vineyards managed by single pruning in the wet season, making the double pruning compulsory.

Vegetative development and berry growth in relation to heat accumulation in Sangiovese vines subjected to double pruning at three different times

The double pruning on Sangiovese based on pre-pruning and finishing in March, April and May applied over three years, induced a postponement of phenological phases, with repercussions on the vine vegetative and berry growth trends, with greater effects, according to the delay in the time of hand follow up during the season. The phenological development, the canopy and berry growth of Sangiovese, subjected to the three different finishing dates for the final pruning, were recorded during three years (2014-2016) and related to day of the year (DOY) and seasonal heat accumulation (growing degree days, GDD). A sigmoid growth model with high coefficient determination (R2 between 0.96 and 0.99), described shoot elongation and herbaceous berry growth, showing a temporal and thermal shift according to the finishing times. Despite the chronological delay, the vines revealed similar thermal necessities. Leaf area evolution of April and May finished vines showed 2 steps: a slow initial development followed by a rapid growth phase (91- 97cm2/GDD) beginning when shoots reached 7–10 leaves. GDD allowed to obtain simple models of vegetative development and berry growth of Sangiovese vines based on thermal evolution.

Advances in the production of temperate fruits in the tropics

The present study aimed to review the advances in the production of temperate fruits to determine future research directions that improve production in the tropics. Temperate fruits are no longer only produced in regions characterized by a cold winter period. These fruits are also produced in the sub-tropical and tropical regions characterized by mild winter or even the absence of chilling conditions often required by the tree to break dormancy. Currently, temperate fruit production is possible in certain regions of South America, Africa and Asia that are near to the Equator. However, temperate tree fruit production in tropical regions requires modified techniques to overcome dormancy and allow adequate flowering, growth and productivity. The main approaches taken are the development of cultivars with low chilling requirement, chemical induction of budbreak, interruption of irrigation during the winter period, defoliation, orchard densification, and double pruning. Breeding has become a key tool in the advancement of temperate fruit growing in the tropics, especially with the development of low chilling requirement cultivars.

Big Data analytics for prediction: parallel processing of the big learning base with the possibility of improving the final result of the prediction

PurposeThis paper aims to solve the problems of big data analytics for prediction including volume, veracity and velocity by improving the prediction result to an acceptable level and in the shortest possible time.Design/methodology/approachThis paper is divided into two parts. The first one is to improve the result of the prediction. In this part, two ideas are proposed: the double pruning enhanced random forest algorithm and extracting a shared learning base from the stratified random sampling method to obtain a representative learning base of all original data. The second part proposes to design a distributed architecture supported by new technologies solutions, which in turn works in a coherent and efficient way with the sampling strategy under the supervision of the Map-Reduce algorithm.FindingsThe representative learning base obtained by the integration of two learning bases, the partial base and the shared base, presents an excellent representation of the original data set and gives very good results of the Big Data predictive analytics. Furthermore, these results were supported by the improved random forests supervised learning method, which played a key role in this context.Originality/valueAll companies are concerned, especially those with large amounts of information and want to screen them to improve their knowledge for the customer and optimize their campaigns.

Increasing the Efficacy of GA3 Sprays in Cluster Elongation and Berry Thinning in Tas-A-Ganesh Grape (Vitis vinifera L.) in Tropical Viticulture

In view of the stage specificity for the efficacy of blanket sprays of GA3 for berry thinning, a field trial was laid out to achieve uniform flowering in Tas-A-Ganesh grapevines subjected to chemical defoliation prior to and hydrogen cyanamide application at fruit pruning in the double pruning and single cropping system during 2013-14 and 2014-15 fruiting seasons in growers’ vineyards around Nashik, Maharashtra by removing the un-uniformly thick canes. GA3 at different doses was sprayed two or three times to address the variation in uniform flowering, if any in cluster elongation and reducing the berry number/cluster. Cane regulation and GA3 sprays were used to achieve uniformity in bud break and flowering. Cluster compactness was derived by multiplying the number of berries/ cm length of rachis with berry diameter. Regression analysis of the variation has revealed that the cane diameter, through uniformity in bud break, influenced the uniformity in flowering which in turn influenced the cluster compactness through increased efficacy of blanket GA3 sprays in reducing the berry number/ cluster. Based on the optimum values of the contributory factors to cluster compactness, cane removal coupled with two blanket sprays of GA3 @ 30 g a.i./ha or retention of all canes coupled with three blanket sprays of GA3 @ 20 g a.i./ha was found to be ideal to obtain loose to well filled clusters. Taking together into account the effect of treatments on cluster compactness, yield and quality, retention of all canes coupled with three sprays of GA3 @ 20 g a.i./ha was considered appropriate for table grape production in Tas-A-Ganesh cv. of grapes.

Increasing the Efficacy of GA3 Sprays in Cluster Elongation and Berry Thinning in Tas-A-Ganesh Grape (Vitis vinifera L.) in Tropical Viticulture

In view of the stage specificity for the efficacy of blanket sprays of GA3 for berry thinning, a field trial was laid out to achieve uniform flowering in Tas-A-Ganesh grapevines subjected to chemical defoliation prior to and hydrogen cyanamide application at fruit pruning in the double pruning and single cropping system during 2013-14 and 2014-15 fruiting seasons in growers’ vineyards around Nashik, Maharashtra by removing the un-uniformly thick canes. GA3 at different doses was sprayed two or three times to address the variation in uniform flowering, if any in cluster elongation and reducing the berry number/cluster. Cane regulation and GA3 sprays were used to achieve uniformity in bud break and flowering. Cluster compactness was derived by multiplying the number of berries/ cm length of rachis with berry diameter. Regression analysis of the variation has revealed that the cane diameter, through uniformity in bud break, influenced the uniformity in flowering which in turn influenced the cluster compactness through increased efficacy of blanket GA3 sprays in reducing the berry number/ cluster. Based on the optimum values of the contributory factors to cluster compactness, cane removal coupled with two blanket sprays of GA3 @ 30 g a.i./ha or retention of all canes coupled with three blanket sprays of GA3 @ 20 g a.i./ha was found to be ideal to obtain loose to well filled clusters. Taking together into account the effect of treatments on cluster compactness, yield and quality, retention of all canes coupled with three sprays of GA3 @ 20 g a.i./ha was considered appropriate for table grape production in Tas-A-Ganesh cv. of grapes.

Calibrated, delayed-cane winter pruning controls yield and significantly postpones berry ripening parameters inVitis viniferaL. cv. Pinot Noir

Background and Aims The postponement of spur pruning after budburst has recently been proposed as a simple and inexpensive way to delay sugaring, maintain acidity and contain yield in spur-pruned trellised grapes. Yet, no long-term data are available for the widely adopted cane pruning system. Methods and Results Mature field grown Vitis vinifera L. cv. Pinot Noir vines were subjected for three consecutive years to the following treatments: standard winter pruning (WP), double pruning (DP), where shortening and positioning of the selected cane is postponed, and late pruning (LP), where all pruning operations are postponed. Postponed pruning was performed when shoot growth from node 10 of the unpruned canes had reached an average stage of more than three unfolded leaves. Phenological and ripening dynamics, yield components and must composition were determined. Double pruning did not affect phenology and overall vine performance compared to that of WP. Conversely, LP significantly delayed ripening over 2 trial years; LP also slightly increased whole-vine and single-cane phenological variability, whereas yield per vine was reduced by 35% as compared to that of WP because of lower shoot fruitfulness. Conclusions If repeated over several seasons, late WP applied to a cane-pruned system when the distal part of the cane has already burst an average of three leaves can become effective at delaying phenology and extending maturity into a cooler season. Significance of the Study We have validated a simple technique suitable for preserving balanced must composition required for a range of sparkling wine styles.

Rootstock on vine performance and wine quality of ‘Syrah’ under double pruning management

In the Brazilian Southeast, the production of high quality wines is attained by a new management approach called double pruning. This management changes the harvesting of wine grape (Vitis vinifera L.) from wet summer to dry winter through a two pruning procedures carried out during the year. The first pruning is done during the winter to induce a vegetative cycle (all clusters are removed) and a second pruning is done during the summer to induce the reproductive cycle. In this study, ten different rootstocks were compared in order to optimize yield and wine quality of Syrah vines conducted under autumn-winter season by double pruning approach. Syrah grapevines grafted onto ‘Rupestris du Lot’ and ‘IAC 766’ showed the highest pruning weight, while ‘110 Richter’ and ‘161-49 Courdec’ induced the lowest cane vigor. The average production of two seasons identified ‘IAC 766’, ‘Kober 5BB’ and ‘Rupestris du Lot’ as the most productive rootstocks. In both seasons, the grape quality was more influenced by the plant development status than by rootstocks. ‘Syrah’ wine from vigorous and high yielding rootstocks, ‘IAC 766’ and ‘Rupestris du Lot’, showed satisfactory wine phenolic composition and alcohol/acidity balance. This study showed that vigorous rootstock increased yield without compromising grape and winter wine quality of Syrah grapevines subjected to double pruning management in the Brazilian Southeast.

Preventative Disease Management and Grower Decision Making: A Case Study of California Wine-Grape Growers.

Preventative disease management is challenging to farmers because it requires paying immediate costs in the hopes of returning uncertain future benefits. Understanding farmer decision making about prevention has the potential to reduce disease incidence and minimize the need for more costly postinfection practices. For example, the grapevine trunk-disease complex (esca, Botryosphaeria dieback, Eutypa dieback, and Phomopsis dieback) significantly affects vineyard productivity and longevity. Given the chronic nature of the infections and inability to eradicate the fungal pathogens, the preventative practices of delayed pruning, applications of pruning-wound protectants, and double pruning (also known as prepruning) are the most effective means of management. We surveyed wine-grape growers in six regions of California on their use of these three practices. In spite of acknowledging the yield impacts of trunk diseases, a substantial number of respondents either choose not to use preventative practices or incorrectly adopted them in mature vineyards, too late in the disease cycle to be effective. Growers with more negative perceptions of cost efficacy were less likely to adopt preventative practices or were more likely to time adoption incorrectly in mature vineyards. In general, preventative management may require strong intervention in the form of policy or extension to motivate behavioral change.

New wine-growing regions of Brazil and their importance in the evolution of Brazilian wine

The objective of this work is to characterize the new Brazilian wine regions, describing their edaphoclimatic and productive characteristics, wine types, and their importance in the evolution of Brazilian wine industry. The Campanha Gaucha is characterized by flat lands, presents a high number of hours of light, and dry summers, guaranteeing a complete maturation of the grapes. Including the locations The Southeastern Region of Rio Grande do Sul presents pronounced ripples, located in altitudes between 400 and 600 m, presenting dry and sunny summers with cold nights, stony soil; Merlot and Cabernet Franc are the outstanding varieties. In the northern plateau of Rio Grande do Sul, at 1000 m a.s.l., the region of Campos de Cima da Serra has a characteristic high solar incidence, and due to the low nocturnal temperatures. The Altitude Region of Santa Catarina State presents similar characteristics to those found in the Campos de Cima da Serra, with vineyards located between 900 and 1400 m, the slow maturation promotes the preservation of acidity and high levels of aromatic compounds, which confer freshness and typical white wines, respectively, especially those made from the Sauvignon Blanc. Located at medium elevations of 900 to 1100 m, the region of Greater Curitiba with hot days and mild nights, stands out for the production of varieties of short to medium cycle, because it presents humid summers favoring the occurrence of diseases fungal infections. The South of Minas Gerais State presents mean altitudes of 800 and 1000 m, in which the technique of double pruning was adopted, leading the grapes maturation to occur during the winter, when a dry season with mild temperatures is found, making it an ideal place to produce high quality Syrah wines. In Sao Paulo State, altitudes between 1,000 and 1,300 m a.s.l. are found, where cool nights and excellent sunshine during the day provide thermal amplitude of 10°C at the time of harvest. Add to this a dry, well-drained and granitic soil, especially for growing Syrah and Viogner. The Sao Francisco River Valley presents flat lands, at an altitude of 400 meters. Located outside the suitable range for growing grapes, this semi-arid region presents low rainfall (less than 500 mm a year) and strong insolation. Its permeable clay soils have proven to be suitable for the acclimatization of grapevines such as Moscatel, Cabernet Sauvignon and Syrah.

Identifying economic hurdles to early adoption of preventative practices: The case of trunk diseases in California winegrape vineyards

Despite the high likelihood of infection and substantial yield losses from trunk diseases, many California practitioners wait to adopt field-tested, preventative practices (delayed pruning, double pruning, and application of pruning-wound protectants) until after disease symptoms appear in the vineyard at around 10 years old. We evaluate net benefits from adoption of these practices before symptoms appear in young Cabernet Sauvignon vineyards and after they become apparent in mature vineyards to identify economic hurdles to early adoption. We simulate winegrape production in select counties of California and find widespread benefits from early adoption, increasing vineyard profitable lifespans, in some cases, by close to 50%. However, hurdles may result from uncertainty about the cost and returns from adoption, labor constraints, long time lags in benefits from early adoption, growers’ perceived probabilities of infection, and their discount rate. Development of extension resources communicating benefits and potential hurdles to growers likely reduces uncertainty, increasing early adoption. Improvements in efficacy of preventative practices, perhaps by detecting when pathogen spores are released into the vineyard, will increase early adoption. Lastly, practice cost reductions will increase early adoption too, especially when the time it takes for adoption to payoff and infection uncertainty are influential in adoption decisions.

Starch accumulation and agronomical performance of Syrah under winter cycle: responses to pruning and ethephon management

In the Brazilian Southeast, 'Syrah' grape harvested during the winter reaches better quality index than those from summer harvest. However, the management of annual double pruning to produce two grapevine growth cycles (vegetative cycle: spring – summer; reproductive cycle: autumn – winter) has increased the vineyard production costs and the vine reserve accumulation can be compromised. This study had two main objectives to improve the winter cultivation: i) to validate single pruning carried out only in summer (February) (experiment 1); to increase the reserve accumulation by ethephon (ethrel) sprayed two months before yield pruning (experiment 2). Both experiments were carried out in south of Minas Gerais State using three years old field-grown 'Syrah' grapevines grafted onto '1103 Paulsen' and trained in a vertical shoot position. The results from experiment 1 showed that grapevines pruned in summer also need to be pruned during the winter after grape harvest to avoid bud infertility during the following autumn-winter season. Single pruning reduced the starch contents in shoots, trunks and roots sampled before yield pruning and the commercial grape harvest was completely unavailable due to unfruitful shoots. On the other hand, the autumn-winter cycle was improved by ethephon sprayed in the previous vegetative growing cycle (summer cycle). During the autumn-winter cycle, sprayed grapevines showed higher starch content in trunks, high vegetative vigor and the yield and grape quality were not negatively affected.

Videira 'Syrah' sobre diferentes porta-enxertos em ciclo de inverno no sul de Minas Gerais

O objetivo deste trabalho foi avaliar a influência de porta-enxertos sobre as características agronômicas, ecofisiológicas e qualitativas da videira 'Syrah' manejada por meio da técnica da dupla poda. As videiras foram enxertadas nos porta-enxertos 'SO4', '110 Richter' e '1103 Paulsen', e sustentadas em sistema espaldeira sem irrigação. Foram avaliadas as características ecofisiológicas, de produção e de composição físico-química das bagas maduras em três safras (2007, 2008 e 2010). Os porta-enxertos não exerceram influência sobre o potencial hídrico de base, que apresentou valores próximos a -0,2 MPa, o que indica que não houve restrição hídrica no solo ao final da maturação (junho). Também não houve diferença significativa quanto à produção. O porta-enxerto '1103 Paulsen' conferiu menor vigor, menor taxa fotossintética e melhores resultados de maturação, para as safras com menores precipitações. Os porta-enxertos '110 Richter' e 'SO4' apresentaram maior vigor nas condições meteorológicas de 2010 e as maiores taxas fotossintéticas para o mesmo período. As condições meteorológicas tiveram efeito significativo na maturação tecnológica e fenólica, com os melhores resultados para os anos mais secos. O porta-enxerto '1103 Paulsen' fornece melhor equilíbrio entre vigor e produção, o que aumenta a qualidade da uva.