Vertical Trellis Research Articles

Building performance modelling approaches for a detached vertical green trellis: A case study in a tropical climate

Passive strategies involving greenery significantly increase energy performance in buildings and comfortable microclimate conditions. However, few studies model and simulate their effect on buildings’ energy performance. Thus, this work assesses modelling approaches for conducting building performance simulations where detached vertical green trellises (DVGT) are included. The DVGT characteristics are modelled by: (i) large solid component blocks and (ii) small opaque solid component blocks to form a grid. A building with glazed façades is evaluated through dynamic simulation under the tropical climate of Panama City, using DesignBuilder. Parametric analysis is performed to study the impact of the trellis configuration on the performance in reducing the annual cooling, lighting, and total electricity consumption. A cost-effective evaluation is also conducted based on the net present value for each trellis configuration. Results showed strong agreement with previous studies reporting significant cooling needs reduction while increasing lighting needs and promising return periods. This concludes that the correct optical and radiative properties of the vegetation layer that are wanted to be modelled in a detached vertical trellis are crucial.

Evaluation of canopy fraction-based vegetation indices, derived from multispectral UAV imagery, to map water status variability in a commercial vineyard

AbstractWater stress is a major factor affecting grapevine yield and quality. Standard methods for measuring water stress, such as midday stem water potential (ΨSWP), are laborious and time-consuming for intra-block variability mapping. In this study, we investigate water status variability within a 2.42-ha commercial Cabernet Sauvignon block with a standard vertical trellis system, using remote sensing (RS) tools, specifically canopy fraction-based vegetation indices (VIs) derived from multispectral unmanned aerial vehicle (UAV) imagery, as well as standard reference methods to evaluate soil and plant water status. A total of 31 target vines were monitored for ΨSWP during the whole growing season. The highest variability was at véraison when the highest atmospheric demand occurred. The ΨSWP variability present in the block was contrasted with soil water content (SWC) measurements, showing similar patterns. With spatial and temporal water stress variability confirmed for the block, the relationship between the ΨSWP measured in the field and fraction-based VIs obtained from multispectral UAV data was analysed. Four UAV flights were obtained, and five different VIs were evaluated per target vine across the vineyard. The VI correlation to ΨSWP was further evaluated by comparing VI obtained from canopy fraction (VIcanopy) versus the mean (VImean). It was found that using canopy fraction-based VIs did not significantly improve the correlation with ΨSWP (NDVIcanopyr = 0.57 and NDVImeanr = 0.53), however fractional cover (fcover) did seem to show a similar trend to plant water stress with decreasing canopy size corresponding with water stress classes. A subset of 14 target vines were further evaluated to evaluate if additional parameters (maximum temperature, relative humidity (RH), vapour pressure deficit, SWC and fractional cover) could serve as potential water stress indicators for future mapping. Results showed that the integration of NDVIcanopy and NDREmean with additional information could be used as an indicator for mapping water stress variability within a block.

Growth, Development and Yield of Golden Currant (Ribes Aureum Pursh.) Depending on Cultivation System

Abstract Although golden currant has been grown in Latvia for several decades, mainly as ornamental plant, there is little experience on the most suitable cultivation systems for berry production. Two cultivars of golden currant — ‘Laila’ and ‘Uzbekistanskaya Krupnoplodnaya’, were planted in 2017 in two cultivation systems — vertical trellis and shrub form and assessed in the first two seasons with harvest. In addition, plots with and without organic mulch were established in the shrub system. The aim of the study was to investigate the growth, development and yield of golden currant depending on the cultivation system. All plants bloomed abundantly and practically at the same time in both years, while no significant differences were found between cultivation systems and cultivars. The annual growth of shoots in 2020 was significantly affected by the cultivation system — on average 0.66 m in the trellis system, 0.41 m in the shrub system in mulched plots, and 0.43 m in unmulched plots. Cultivar ‘Laila’ tended to produce longer shoots (average 0.51 m) than the ‘Uzbekistanskaya Krupnoplodnaya’ (average 0.47 m). The yield was low because of poor fruit set and did not significantly differ between cultivar and cultivation systems, though cultivar ‘Laila’ and shrub systems still had higher yields.

The Umbrella Type Canopy Increases Tolerance to Abiotic Stress-Leaf Microenvironment Temperature and Tropospheric Ozone in ‘Chambourcin’

This study reports on the effect of the vertical shoot type canopy (VST) and umbrella type canopy (UT) on the fruit region microenvironment, light interception, tropospheric ozone, and berry quality of vertical trellis ‘Chambourcin’. The real-time temperature and humidity fluctuation and the daily average temperature of the UT canopy were lower than that of the VST canopy. An extremely high temperature was recorded around the fruit region of the VST canopy. Notably, the UT canopy significantly increased light interception and leaf area index and reduced the damage of atmospheric ozone to the leaves. These phenomena increased the content of soluble solids, anthocyanins, total phenols, flavonoids, and flavanols in the mature fruits of the UT canopy more than in the VST canopy. In conclusion, the UT canopy saves shoot management labor and improves the fruit region’s microenvironment and the content of anthocyanins, total phenols, flavonoids, and flavanols.

Effect of trellis orientation on Passiflora incarnata growth and production

Passiflora incarnata L., often referred to commonly as ‘maypops’, has showy flowers and large fruit. This species has been identified in historical documents as being a food crop, although it is not presently grown as a commercial crop. To better facilitate harvest, Passiflora vines must be trellised to keep flowers and fruit off the ground. There are different methods to accomplish this, but there is little consensus as to the best model. Simple trellis systems made from t-posts, wire fencing, and cement blocks were erected onto a crushed rock covered nursery pad. One trellis was made horizontal to the ground roughly 0.3 m off the pad. The other trellis was vertical (perpendicular to the ground) and reached a height of 1.5 m. Three Passiflora species were used: Passiflora caerulea L. (blue passion flower), Passiflora edulis Sims f. flavicarpa O. Deg. (yellow passion fruit), and Passiflora incarnata (maypop). There were no statistically significant differences between vertical and horizontal trellised passion fruit vines in our study. Overall, trellis orientation did not appear to significantly impact vine growth, fruit growth, or fruit quality of Passiflora incarnata. We recommend employing a vertical trellis system for this species.

Influence of various types of absorbent and mulching materials on the productivity and quality of the harvest of cucumbers in the Forest-steppe of Ukraine

The article presents three year’s data on the influence of various types of absorbent and mulching materials on the productivity of Bettina hybrid cucumber for growing plants on a vertical trellis in the Forest-steppe conditions of Ukraine. The data on the passage of the main phenological phases of growth and development of cucumber plants, biometric parameters, yield and biochemical composition of fruits, correlation and variance analysis of the research results are presented. It was found that all phases of plant growth and development passed faster when the soil was mulched with black plastic wrap and black agro fbre using different types of absorbent. In comparison with the control, water-retaining granules and gel, against the background of the use of mulching materials, contributed to an increase in the height of the main stem, the formation of a larger number of leaves on the plant and the area of their assimilation surface. Among the mulching materials, the best results were obtained with the black flm, and among the types of absorbent - with the gel. The highest marketable yield was obtained from the options for mulching the soil with black plastic wrap using water-retaining granules and gel – 56,4 t/ha and 56,9 t/ha, respectively. The largest mass of the early harvest was provided by the option of mulching with a black flm and applying gel to the soil – 35,9 t/ha. Mulching materials and various types of absorbent have contributed to the increase in the marketability of the crop. However, the largest marketability was in the option of mulching with black flm and the use of water-containing granules – 99,4 %. Under the influence of mulching materials and various types of absorbent, the biochemical composition of cucumber fruits changed. The highest dry matter content was for mulching with black flm and the use of an absorbent – 5,3 %. The most sugary fruits were those with the option of mulching with a flm and using an absorbent in the form of a gel – 2,19 %. The content of nitrates in fruits did not exceed the maximum permissible level. However, their lowest content in fruits was under agro fbre without the use of an absorbent – 52,0 mg/kg. Key words: cucumber, hybrid, vertical trellis, absorbents, mulching materials, biometric indicators, yield, fruit marketability, crop quality.

Robotics-based vineyard water potential monitoring at high resolution

The purpose of this research is deploying a proximal sensing solution using non-invasive and cost-effective sensors onboard an Autonomous Ground Vehicle (AGV) as a feasible way for building high-resolution maps of water potential in vineyards. The final objective is offering growers a practical system to make decisions about water management, especially for arid climatic conditions. The monitoring AGV was entirely developed within this research context, and as a result, it is a machine specifically designed to endure off-road conditions and harsh environments. The autonomous vehicle served as a massive, non-invasive, and on-the-go data collector robotic platform. The sensors used for measuring the relevant field variables were two spectral reflectance sensors (SRS), an infrared radiometer, and an on-board weather sensor. The collected data were displayed on comprehensible grid maps using the Local Tangent Plane (LTP) coordinate system. The proposed model has a coefficient of determination R2 of 0.69, and results from combining six parameters: the canopy and air temperatures (as the temperature difference), the relative humidity, the altitude difference, the Normalized Difference Vegetation Index (NDVI), and the Photochemical Reflectance Index (PRI). The strongest relationships found in this study were between the temperature difference and PRI, with an R2 of 0.75, and the temperature difference with the leaf water potential with an R2 of 0.61. The practical use of these high-resolution maps includes irrigation scheduling and harvest zoning for sorting grape quality, with a further use as inputs to complex artificial intelligence algorithms considering larger areas or complementing airborne data. Future improvements to make the models more robust and versatile will entail considering additional variables, locations, or grapevine cultivars, and even other crops grown in vertical trellis systems.

Physicochemical and aromatic composition of 'Sauvignon Blanc' wines obtained from the Y-trellis and VSP training systems

Abstract: The objective of this work was to compare the effect of the Y-trellis and vertical shoot position trellis (VSP) training systems on the physicochemical composition and aromatic profile of 'Sauvignon Blanc' (Vitis vinifera) wines in a high-altitude region of the state of Santa Catarina, Southern Brazil. The experiment was conducted during the 2015 vintage in a commercial vineyard located in the municipality of São Joaquim. The treatments consisted of the training systems: Y-trellis and VSP pruned in spur cordon. Sixty kilograms of grapes were harvested from each training system to make the wines, which were evaluated as to their chemical and phenolic composition and aromatic profile. There is no effect of the training system on the wine chemical variables pH, total acidity, color, and total polyphenols. The aromatic profile and phenolic composition of the wines are affected by the training systems, being related to the variables ethyl acetate, isoamyl acetate, 3-methyl-1-butanol, propanoic acid, and gallic acid in the Y-trellis, and to 1-hexanol, isovaleric acid, caprylic acid, capric acid, and catechin in VSP. The Y-trellis system can be an alternative for high-altitude regions of Southern Brazil.

Spraying Ozonated Water on Bobal Grapevines: Effect on Wine Quality.

Ozonated water is being introduced as an alternative phytosanitary treatment to control grapevine diseases in a context in which the reduction of chemical pesticides has become an urgent necessity. In this study, we evaluated the effect of spraying grapevines with ozonated water on the enological, phenolic, and aromatic qualities of Bobal wines during two consecutive growing seasons. In the first season, ozonated water was applied once during the ripening period on grapevines trained on the traditional gobelet system (S1). In the second season, three applications were performed between fruit set and harvest on grapevines grown on a vertical trellis system (S2). The S1 treatment led to a wine with an increased alcoholic degree and a remarkably higher phenolic content, which resulted in preferable chromatic characteristics. The S2 treatment maintained the total phenolic content but significantly enhanced stilbenes and flavanols and also reduced anthocyanins, which negatively affected the wine colour. Regarding aroma, both treatments reduced the content of glycosylated precursors and had different effects on free volatiles, both varietal and fermentative. Thus, the metabolic response of grapevines to the ozonated water stress, and therefore the quality of wines, depended on the ozone dose received by the plants.

Producers profile and the adoption of technologies in passion fruit cultivation in the Triângulo Mineiro region

Abstract Productivity of passion fruit in Brazil varies widely among producers in different states and regions depending on the adoption of technologies. In this study, the goal was to evaluate the producers profile and use of technologies in passion fruit production in the Triângulo Mineiro region, driven by the local juice industry. The research was carried out from 2018 to 2019, using Behavioral Diagnosis of Productive Activity methodology, based on questionnaires applied to 22 producers in eight cities. The data were submitted to descriptive and multivariate statistical analysis. Most producers grow passion fruit in up to 5 ha, in a family work regimen, and have little experience. The cultivation system is open field in vertical trellis, with a production cycle of 1.5 years. The great majority use manual pollination, chemical and organic fertilization, and do not systematically adopt integrated phytosanitary management. The seedlings are purchased from qualified nurseries and the most planted cultivar is the FB 300. The main losses reported by producers were caused by drought and damage to floral bud, with an average fruit yield of 17 t ha-1 year-1. This production chain is structured but requires technical interventions to increase the profitability and sustainability of the production system.

Alternative budburst management in Campanha Gaúcha vineyards

Abstract Seeking a less toxic alternative to budburst management than hydrogen cyanamide, doses of the mineral-organic product Erger® were tested in combination with calcium nitrate (Ca(NO3)2). The experiment was conducted in Santana do Livramento, southern Brazil, during the 2013/14 and 2014/15 growth cycles, in a ‘Merlot’ vineyard conducted in a vertical trellis system, pruned in double Guyot, with SO4 rootstock. Treatments were: Control (unsprayed); 5.0% Ca(NO3)2; 2.5% Erger® + 5.0% Ca(NO3)2; 5.0% Erger® + 5.0% Ca(NO3)2; 7.5% Erger® + 5.0% Ca(NO3)2; 3.5% Dormex® (positive control). All Erger® treatments stimulated budbreak, increasing budburst from 68% (unsprayed and calcium nitrate means) to 83% (Erger® means) in the first cycle and from 85% to 96% in the second one, with no difference among doses. Plants treated with Dormex® had budburst similar to Erger® in the first cycle (85%), but budburst in the second cycle was only 72%, possibly due to burned buds. Therefore, Erger®, in concentrations of 2.5% or more with 5% calcium nitrate, may be a promising alternative to induce budburst in regions with restrictions in cold availability.

Spraying ozonated water on Bobal grapevines: Effect on grape quality

Ozone is a powerful oxidant that is increasingly used as sanitizing agent in the wine industry and even in the vineyard to control grapevine diseases. In this study, we evaluated the effect on grape enological quality of ozonated water spraying treatments carried out in Bobal grapevines during two consecutive harvest seasons. In the first season, ozonated water was applied once during the ripening period on grapevines trained on the traditional gobelet system (S1). In the second season, ozonated water was applied three times between the fruit set and harvest on grapevines grown on a vertical trellis system (S2). Grape quality on harvest day was evaluated through several enological and chromatic parameters, the phenolic maturity, the Varietal Aroma Potential Index (IPAv) and the phenolic and volatile composition. The S1 treatment had a positive effect on the technological maturity, the chromatic parameters, the seed maturity and the content of glycosylated aroma precursors, phenolic compounds and free terpenoids of grapes. The S2 treatment also improved the technological maturity and the content of total anthocyanins (pH 1.0) and free terpenoids, but had a negative impact on the chromatic parameters, the anthocyanin extractability and the content of glycosylated aroma precursors and phenolic compounds. Therefore, ozonated water sprayed on Bobal grapevines affected the quality of grapes, but the effect seemed to depend on the number of applications.

The significance of scion × rootstock interactions

Aims: Rootstocks provide protection against soil-borne pests and are a powerful tool to manipulate growth, fruit composition and wine-quality attributes. The present study aimed to assess the consistency of rootstock effects on the growth and fruit composition of scion varieties and identify scion × rootstock interactions.Methods and results: Vine performance and fruit composition of hot-climate, drip-irrigated, spur-pruned Chardonnay, Cabernet Sauvignon and Shiraz, grafted on seven rootstocks, was assessed over five seasons from 2013 to 2017. Rootstocks included Ramsey, 1103 Paulsen and 140 Ruggeri and four promising selections from the CSIRO rootstock development programme. Vines were trained as quadrilateral cordons on a two-wire vertical trellis of height 1.8 m and 3.0 m row × 1.8 m vine spacing, and irrigated with 5.5–6.0 ML/ha of water each season. The study was conducted with mature vines, established in 2006, as a randomised block design with five replicates. There were significant effects of both variety and rootstock on yield, number of bunches, bunch weight, berry weight (scion only), berries per bunch, pruning weight and the Ravaz Index (yield/pruning weight). Despite identical management practices, there were large differences between scion varieties in key growth characteristics across rootstocks. Chardonnay produced a high yield (mean 25.2 kg/vine) with low pruning weight (2.3 kg/vine) and a high mean Ravaz Index value of 12.1. Shiraz had the highest yield (27.4 kg/vine) with high pruning weight (5.1 kg/vine) and a Ravaz Index of 6.3. Cabernet Sauvignon had the lowest yield (15.9 kg/vine) and highest pruning weight (6.6 kg/vine) and a very low Ravaz Index value of 3.0. Effects of rootstock on growth characteristics were smaller than the effects of variety, with mean yields ranging from 19.5 to 25.9 kg/vine, pruning weights ranging from 3.24 to 6.13 kg/vine and mean Ravaz Index values ranging from 5.54 to 8.63. Each variety was harvested when the mean total soluble solids reached 25.0 °Brix. Significant effects of variety and rootstock on fruit composition, included pH, titratable acidity (scion only), malate, tartrate (scion only), yeast assimilable nitrogen (YAN); and for the red varieties, total anthocyanins (scion only) and phenolic substances (scion only). Significant interactions between scion variety and rootstocks were found for yield, number of bunches, berry weight, pruning weight and Ravaz Index. The effect of rootstock on bunch weight and berries per bunch was consistent across scions. Significant scion × rootstock interactions were also found for pH and YAN. For each variety, significant effects of rootstock on fruit composition were linked to growth characteristics. However, these relationships, based on correlation analyses, varied for each scion.Conclusions: The study has shown that growth characteristics and fruit composition of the major varieties was not consistent across seven rootstock genotypes, as significant scion × rootstock interactions were determined. Hence, different rootstocks may be required for each variety to optimise scion performance and fruit composition. The study has also shown that the new CSIRO rootstock selections, covering a range of vigour classifications, may be useful alternatives to those currently in use by industry.Significance and impact of the study: The study has shown that the performance of scion varieties, and to a lesser degree the fruit composition, is dependent on rootstock choice. The inherent vigour of the scion variety must be considered in rootstock selection. Furthermore, individual scion/rootstock combinations may require specific irrigation, pruning or canopy management to achieve vine balance and optimise fruit and wine composition.

Physical-chemical and chemical characterization of Passiflora cincinnata Mast fruits conducted in vertical shoot positioned trellis and horizontal trellises system

Abstract Passiflora cincinnata Mast. or Caatinga passion fruit is widely cultivated in the northeastern semi-arid regions of Goiás, Minas Gerais, and Bahia. The system of cultivation and field management of the Passiflora species affects the physicochemical quality of its fruits. In this study, we evaluated the chemical and physico-chemical characteristics of the fruits of 2 progenies (CPEF2220 and CBAF2334) of P. cincinnata species using the vertical and horizontal trellis system. Fruits were collected from the plants at their physiological maturation stage and tested for the fruit skin color and texture and the pH, total soluble solids, titratable acidity, pulp acidity ratio, and the contents of flavonoids, anthocyanins, and polyphenols in the seedless fruit pulp. The experimental design was completely randomized in a 2 x 2 factorial scheme (progenies x conduction system) performed in 3 replications using 4 plants in each. The analysis of variance and the means were compared using the Tukey’s test at 5% probability. The results revealed that the CBAF2334 fruits presented with greener pigments and greater flavonoids. The fruits were characterized by their green color with some yellowish nuances and a low color saturation in both the progenies. The conduction system was not found to affect the physical and physicochemical characteristics as well as the anthocyanin and polyphenol contents of the studied species. The fruits of plants cultivated on vertical trellis presented with 56.73% more flavonoid content than those cultivated on horizontal trellis.

Phenology and thermal requirements of grapevine cultivars in Dois Vizinhos, Paraná State, Brazil

ABSTRACT: This study aimed to characterize the phenology and thermal requirements of grapevine cultivars Bordô, BRS Carmem, BRS Lorena, BRS Magna, BRS Rubea, BRS Violeta, Concord, Concord Clone 30, Isabel, Isabel Precoce, Moscato Bailey, Moscato Embrapa, Niagara Branca, Niagara Rosada, and Seibel 5455 grafted on Paulsen 1103. The study was conducted in the fruit growing sector of the Federal Technological University of Paraná, Câmpus Dois Vizinhos, Paraná State, Brazil, during the cycles of 2015/2016 and 2016/2017. The experimental design was completely randomized, with four replicates and two evaluated plants per plot. Plants were grown in a vertical trellis system and spur pruned with two buds. Evaluations of phenology and thermal requirements were carried out from pruning to harvest. Cultivars Moscato Bailey and Seibel 5455 had high thermal requirements and longer cycles, while cultivars BRS Magna, BRS Violeta, and Isabel Precoce had lower thermal requirements and shorter cycles. The cycle and the thermal requirements of cultivars ranged from 98 to 132 days, and from 1065 to 1548 degree-days, respectively.

Public perceptions and attitudes toward green infrastructure on buildings: The case of the metropolitan area of Athens, Greece

As the impact of green space shrinkage in urban centers becomes obvious, local and regional authorities must adopt environmental planning policies that can help create new green areas to ensure a good quality of life for citizens, along with the rehabilitation of the natural environment. One approach is the promotion of green infrastructure on buildings, including multi-dwelling apartment buildings. In order to effectively promote green infrastructure on buildings, it is essential to comprehend public attitudes toward green infrastructure, so that suitable and effective strategies can be implemented by policy makers. In this study, eight hundred respondents were asked to provide their views on green infrastructure on buildings, on construction that should take place on blocks of apartments in order to accommodate green infrastructure and on the related benefits that may arise from creating green spaces on buildings. A structured questionnaire and stratified sampling were used for the interviews, which were conducted with apartment owners in two regional units of Athens. The results showed that most citizens are willing to proceed with the installation of a green roof, trellis or vertical garden, in order to improve the aesthetics and functionality of the building they live in. Most of the respondents are not familiar with the energy savings that may occur from the installation of a green roof, vertical trellis or garden and wish for a subsidy from the state in order to implement green building solutions. To conclude, the participants in our study are not environmentally aware, since they are not interested in energy conservation but only about the aesthetics of their building; furthermore, they expect to receive financial support from the state in order to make any changes to their home.

Yellow passion fruit in overhead trellis system do not differ in diseases intensity and is more productive compared to vertical trellis system

Abstract Brazil is the largest producer of passion fruit worldwide, however diseases have been reducing passion fruit productivity, and limiting its cultivation for several years in a row in the same area. The proposal of this study was to evaluate diseases intensity and productivity of yellow passion fruit in vertical and overhead trellis systems, during two seasons, in annual cycle. The experiment was realized in a commercial orchard of yellow passion fruit in the municipality of Araquari, SC, in the 2013/14 and 2014/15 seasons. The treatments were vertical and overhead trellis systems, tested in a randomized complete block design, with eight replications. The agronomic practices were performed according to the culture recommendations and naturally pollinated althoght no disease control was applied. Anthracnose, bacterial blight, cladosporiosis and passion fruit woodiness severities were assessed in two seasons, from December to June, after establishment of the trellis systems. Production of fruits per plant and estimated productivity were determined in both seasons. There were no differences in diseases severity in both systems and seasons. The overhead trellis system was more productive than the vertical trellis system, 78.1% and 57.1% respectively, in the 2013/14 and 2014/15 seasons. Overhead trellis system showed to be the most adequate for yellow passion fruit production.

Row Orientation and Defoliation Effects on Grape Composition ofVitis viniferaL. Agiorgitiko in Nemea (Greece)

Vineyard row orientation and canopy side exert a significant role in determining grape microclimate. The latter can be further manipulated by selective defoliation in the bunch zone. The aim of this study was to investigate the combined effects of row orientation and basal leaf removal on grape ripening of Vitis vinifera L. cv. Agiorgitiko in Nemea, Southern Greece. The experiment was conducted in 2017, on two adjacent vineyard blocks planted in 1990 on a flat site with two row orientations, North-South and East-West. Both blocks were grafted onto 41B rootstock and trained on a double cordon vertical trellis with uniform vineyard operations. Defoliation treatments included full leaf removal in the bunch zone performed at berry set and a non defoliated control, replicated three times in both blocks. Grapes were sampled at three time points from veraison to harvest from all canopy sides (i.e. E and W on North-South oriented rows and N and S on East-West oriented rows) and defoliation treatments and were analyzed for yield components and berry chemical composition. In addition, approximately 5 kg of grapes were collected from all plots and processed according to a standard winemaking protocol. Total yield and berry mass were lowest in the W-exposed and in the defoliated grapes. Must sugar and acid content, as well as wine alcohol and acidity did not depend on either factor. Skin anthocyanins and phenolics generally increased with defoliation. Skin anthocyanins and total berry phenolics were highest for north-south oriented rows, in the grapes of the cooler canopy side (E). Wines made from grapes of the E and W canopy sides showed the highest wine color, phenolic richness and the lowest pH. No interaction between row orientation and defoliation was detected for any of the measured parameters. According to the results, the E-facing grapes on the north-south oriented rows showed generally a superior grape and wine composition for Agiorgitiko variety, under the semiarid conditions of the Nemea area.

Automated Detection of Branch Shaking Locations for Robotic Cherry Harvesting Using Machine Vision

Automation in cherry harvesting is essential to reduce the demand for seasonal labor for cherry picking and reduce the cost of production. The mechanical shaking of tree branches is one of the widely studied and used techniques for harvesting small tree fruit crops like cherries. To automate the branch shaking operation, different methods of detecting branches and cherries in full foliage canopies of the cherry tree have been developed previously. The next step in this process is the localization of shaking positions in the detected tree branches for mechanical shaking. In this study, a method of locating shaking positions for automated cherry harvesting was developed based on branch and cherry pixel locations determined using RGB images and 3D camera images. First, branch and cherry regions were located in 2D RGB images. Depth information provided by a 3D camera was then mapped on to the RGB images using a standard stereo calibration method. The overall root mean square error in estimating the distance to desired shaking points was 0.064 m. Cherry trees trained in two different canopy architectures, Y-trellis and vertical trellis systems, were used in this study. Harvesting testing was carried out by shaking tree branches at the locations selected by the algorithm. For the Y-trellis system, the maximum fruit removal efficiency of 92.9% was achieved using up to five shaking events per branch. However, maximum fruit removal efficiency for the vertical trellis system was 86.6% with up to four shakings per branch. However, it was found that only three shakings per branch would achieve a fruit removal percentage of 92.3% and 86.4% in Y and vertical trellis systems respectively.

Defoliation of two-wire vertical trellis: effect on grape quality

ABSTRACTBasal leaves were removed from Cabernet Sauvignon vines trained to a two-wire vertical trellis at fruit set and at veraison. Leaf removal did not modify total soluble solids and titratable acidity at harvest. Defoliation at fruit set of lower cordon recovered the grape anthocyanin composition gap between upper and lower cordons and that produced a positive effect on anthocyanin synthesis. Hence, control of the upper cordon and defoliation of fruit set of the lower cordon treatments showed comparable values of anthocyanins. Defoliation at veraison did not produce any appreciable effect. This study shows that skin anthocyanin composition in a two-wire vertical trellis can be modified by leaf removal in the fruit zone of the lower cordon, reducing variability in the ripeness between the two cordons.