Canopy Management Research Articles

Canopy Management of the Great Banyan Tree in Acharya Jagadish Chandra Bose Indian Botanic Garden, Howrah, India

The present communication deals with the prop root training of Great Banyan Tree (GBT) of Acharya Jagadish Chandra Bose Indian Botanic Garden (AJCBIBG), Botanical Survey of India, Howrah. The GBT spans an area of 4.86 acres and features over 4400 aerial prop roots, covering a canopy circumference of 543 meters. Notably, the tree has survived three major cyclones, including the latest one, Amphan, on May 20, 2020, which significantly impacted a major portion of the tree. To address the damage caused by all cyclones and facilitate the expansion of the GBT, the AJCBIBG Authority is continuously working to train the prop roots for improving of canopy management using indigenous techniques developed by the staff over a decade for this age-old tree.

Variations Among Crop Seasons and Inoculum Availability Have a Higher Impact on Grapevine Rust Epidemics than Training Systems or Plastic Cover.

Canopy management practices can be effective as part of the integrated management of grapevine diseases. This study aimed to determine whether training systems and plastic covers can contribute to prevent Asian grapevine leaf rust (AGLR) development. Additionally, the influence of crop season and inoculum availability on AGLR development was investigated. Six-season experiments were carried out to characterize 16 epidemics that developed from natural inoculum (NI) or artificial inoculum (AI) sources (NI + AI), conducted in different training systems and with or without the plastic cover. The Richards model was fitted to each AGLR disease progress curve to estimate and compare the onsets and intensities of epidemics using eight curve elements. Principal components analysis (PCA) identified the incidence progress rate, the area under the severity progress curve, final disease severity, time to disease onset, and time to reach the inflection point as the main descriptors for AGLR epidemics. The results showed that AGLR epidemic development was related mainly to differences in inoculum availability and climatic conditions throughout the seasons and to a lower extent to the training system and plastic cover. The earliest disease onset was observed in epidemics when the NI was supplemented with an AI source. Differences in AGRL intensity were correlated to accumulated precipitation, being less severe in autumn-winter than in the spring-summer season. The present findings provided a better understanding of the structure and the seasonal variation of AGLR in cultivar 'Niagara Rosada'. The strategies for reducing and/or delaying inoculum buildup among seasons are discussed.

Studied the growth, yield and quality attributes of guava as influenced by Canopy management practices: A review

Studied the growth, yield and quality attributes of guava as influenced by Canopy management practices: A review

Zeolite application and irrigation during ripening reduced berry sunburn damage and yield loss in cv. Sangiovese (Vitis vinifera L.).

Climate change poses significant challenges to the grapevine cultivation for wine production. In the last years, the occurrence of extreme weather events such as intense heat waves and prolonged period of drought increased sunburn damage with negative consequences to yield and berry composition. Short-term adaptation strategies are urgently needed to mitigate these effects. In this light, our study aimed to evaluate the efficacy of zeolite application on the canopy and irrigation during ripening on sunburn damage, yield, and berry composition in cv. Sangiovese (Vitis vinifera L.). Over 3 years (2021-2023), canopy management and irrigation treatments were arranged in a strip-plot design. Canopy management treatments included leaf removal on the cluster zone, with and without zeolite application, and no defoliated control; irrigation treatments comprised irrigation from berry softening and no irrigation. Both zeolite application and irrigation reduced sunburn damage, thus mitigating yield loss. Regarding berry composition, zeolite application did not alter the main parameters whereas irrigation led to reductions in sugar and anthocyanin concentrations. These findings suggest that zeolite application and irrigation during ripening represent promising and cost-effective solutions for grape growers facing climate change-induced challenges. However, further studies are necessary to optimize timing of irrigation to avoid detrimental effects on anthocyanin accumulation.

Automated System for Continuous Green Shoot Thinning in Vineyards

Highlights An automated green shoot thinning system was developed by integrating machine vision and mechanical systems. Mask R-CNN used for segmenting cordons at different shoot growth stages. Point cloud registration used to accurately stitch cordon trajectories for continuous thinning operation. Field and lab tests demonstrated the integrated system can efficiently automate green shoot thinning operation. Abstract. Mechanized green shoot thinning in vineyards has helped reduce labor and associated costs. However, high variability in the thinning efficiency has been observed with the current machines in non-selective thinning due to challenges faced by the operators to precisely position thinning end-effectors along the cordon trajectories. In this study, an automated green shoot thinning system is proposed for cordon-trained grapevines to enhance the precision and efficiency of mechanical thinning operation. The automated system consisted of (1) a machine vision system for estimating cordon trajectories and (2) a mechanical system to position thinning rollers along the estimated trajectories during the real-time thinning operation. The vision pipeline used a Mask R-CNN model to determine cordon profiles at different shoot growth stages and a depth image to estimate the 3D cordon trajectory. In addition, point-cloud registration estimated transformation matrices for accurately stitching adjacent cordon trajectories and generating a long map of trajectory for the thinning rollers to follow. An image processing-based calibration method was used to obtain transformation parameters that transformed the estimated trajectories from the camera coordinate space to the thinning-roller coordinate space required for trajectory following. Lab tests, conducted using simulated cordons, showed the integrated system can precisely position the thinning rollers with root mean square errors (RMSE) of 2.0 cm and 1.7 cm for vertical and lateral positions, respectively. To quantify the thinning performance of the integrated system in the field, shoot thinning efficiency (the percentage of target shoots impacted) was determined. From the field evaluation, shoot thinning efficiency of 76% and 85% were achieved for two rows of grapevines, with an overall shoot thinning efficiency of 80%. The favorable test results demonstrated that the proposed integrated system is capable of effectively automating green shoot thinning operations, which has the potential to improve shoot thinning performance in vineyards. Keywords: Automated green shoot thinning, Cordon trajectory estimation, Mask R-CNN, Vineyard canopy management.

Vineyard canopy management techniques to cope with climate change

Vineyard canopy management techniques to cope with climate change

Epidemiology and control of strawberry powdery mildew: a review

Strawberry powdery mildew, caused by Podosphaera aphanis, is an economically important disease for strawberry production. Typical symptoms are white mycelium on all aerial parts of affected plants, with young host tissues being the most susceptible. The pathogen overwinters on infected leaves, either as mycelium or chasmothecia, although the quantitative role of chasmothecia in epidemics are not fully understood. In spring, under favourable conditions, the fungus sporulates, disseminating conidia and causing polycyclic infections. The disease is mainly controlled using synthetic fungicides, but there is increasing interest in sustainable alternatives, including microbial biocontrol agents (e.g., Ampelomyces quisqualis, Bacillus spp., Trichoderma spp.) and substances of plant or animal origin (e.g., Equisetum arvense, orange oil, chitosan, whey). Physical methods, (e.g. UV-C, ozone) are also promising alternatives to fungicides. All of these strategies should be combined with appropriate agronomic practices (e.g., overhead irrigation, canopy management) to create unfavourable environments for the pathogen. However, agronomic practices have never been assessed for P. aphanis. Disease forecasting models and DSSs, though available, are underutilized due to their complexity and lack of validation across locations. This review presents the current state of knowledge on P. aphanis the available methods for control of strawberry powdery mildew, and highlights knowledge gaps relating to this host/pathogen relationship.

Effect of the grape thinning on the content of trans-resveratrol in some Syrah clones

Wine is a product obtained through fermentation process, the trans-resveratrol is a polyphenol derived from grapes and a natural antioxidant that passes into wine. The trans-resveratrol is a rare compound with the highest content in the red wine and a positive physiological effect on human organism. The present study was conducted in three years period from 2020 until 2022 at the Agricultural university-Plovdiv experimental vineyard, located near the village of Brestnik. Four Syrah wine variety clones were included and eight experimental wines have been made during the experimental period. In all tested wines, the presence of trans-resveratrol was detected but its amount was higher in clone 524 (V4) with non-reduced yield (3.35, 4.36, 7.02 mg/L), and in clone 100 (V5) with reduced yield (5.24, 3.75, 7.23 mg/L). Reducing the bunch numbers at the “pea size” stage did not significantly influence the content of trans-resveratrol. The wine antioxidant properties were directly affected by the clone and the grape harvest and was under the terroir influence. In today's conditions of overproduction and increased competition, the results of this study provide a valuable economic information and expand the portfolio of wineries. Keywords: clones, Syrah, red wine, resveratrol, bunch thinning, canopy management

Rootstocks: Importance in Fruit Crop Improvement

India is the second largest producer of fruits in the world with different fruit growing zones viz., temperate, arid and semi-arid, subtropical, and tropical zones. In this present era of climate change, fruit growers are facing environment-related problems such as sudden changes in temperature, irregular and heavy rainfall, and soil-related problems like compaction, salinity, alkalinity, and acidity. In addition to this, pest and disease incidence also play a major role in limiting fruit production. Objectives of rootstock breeding includes resistance or tolerance to biotic stress, adaptability to soil and environmental conditions, dwarfism, precocity in bearing, high yield and good fruit quality. The purpose of rootstock breeding varies with crops and geographical locations. Developing rootstocks resistant or tolerant to biotic stresses in apple (fire blight and woolly apple aphid), citrus (root rot, nematodes and viral diseases), grape (Phylloxera spp. and nematode) and mango (mango fruit fly and stone weevil) for specific tree characters (dwarfing, canopy management) and horticultural traits (yield and quality) are the important aspects in rootstock breeding. The reported rootstocks which are impactful in fruit cultivation like apple (MM-111), grape (Dogridge, 99-R, 110-R and 1103-P), and mango (Turpentine, Deorakhio and Olour). The use of rootstocks which are tolerant or adaptable to adverse climatic situations and biotic stress can be an alternative option for scientists and fruit growers to face the challenges encountered by the fruit industry.

Advancements in Drone Technology for Fruit Crop Management: A Comprehensive Review

Drones, or Unmanned Aerial Vehicles (UAVs), equipped with advanced sensors and imaging capabilities, have revolutionized the way farmers monitor and manage fruit crops. Aerial surveillance enables high-resolution imaging of orchards and vineyards, allowing for early detection of diseases, pests, and other stress factors that can impact crop health. The data collected by drones facilitate precise and targeted interventions, optimizing resource use and enhancing overall crop productivity. Additionally, drones contribute to yield estimation, canopy management, and post-harvest monitoring. While the technology offers significant advantages, challenges such as payload limitations, weather sensitivity, and regulatory compliance must be addressed. Ongoing research and technological advancements are expected to overcome these limitations, further establishing drones as indispensable tools for sustainable and efficient fruit crop management. This review consolidates current knowledge, highlights emerging trends, and outlines future prospects for the integration of drone technology in fruit agriculture.

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.

Managing Spring rain risks in vineyards: A user-centred approach to identify climate decision triggers in seasonal forecasts

In the context of climate risk mitigation strategies seasonal forecasts have been often proposed as a potential climate risk management tool for the wine industry. However, in spite of the recent research advancements, the adoption of climate predictions in strategic decision-making remains complex. This paper aims to support decision-making in the wine sector by providing a methodology to establish the probability thresholds that can trigger a decision based on seasonal forecasts, in an illustrative setting where precipitation occurring in spring could heavily affect the effectiveness of plant protection and canopy management. The results show the probability thresholds obtained for the user involved and the specific decision under three different predicted scenarios. The advantages of this co-production methodology consist in the trust created by the engagement with the user and the high level of tailoring of the analysis performed, posing the basis for user risk profile analysis. The drawbacks lay in the use of a simplified theoretical framework and the need of engaging new users for replication.

Assessing automatic data processing algorithms for RGB-D cameras to predict fruit size and weight in apples

Data acquired using an RGB-D Azure Kinect DK camera were used to assess different automatic algorithms to estimate the size, and predict the weight of non-occluded and occluded apples. The programming of the algorithms included: (i) the extraction of images of regions of interest (ROI) using manual delimitation of bounding boxes or binary masks; (ii) estimating the lengths of the major and minor geometric axes for the purpose of apple sizing; and (iii) predicting the final weight by allometric modelling. In addition to the use of bounding boxes, the algorithms also allowed other post-mask settings (circles, ellipses and rotated rectangles) to be implemented, and different depth options (distance between the RGB-D camera and the fruits detected) for subsequent sizing through the application of the thin lens theory. Both linear and nonlinear allometric models demonstrated the ability to predict apple weight with a high degree of accuracy (R2 greater than 0.942 and RMSE < 16 g). With respect to non-occluded apples, the best weight predictions were achieved using a linear allometric model including both the major and minor axes of the apples as predictors. The mean absolute percentage error (MAPE) ranged from 5.1% to 5.7% with respective RMSE of 11.09 g and 13.02 g, depending to whether circles, ellipses, or bounding boxes were used to adjust fruit shape. The results were therefore promising and open up the possibility of implementing reliable in-field apple measurements in real time. Importantly, final weight prediction error and intermediate size estimation errors (from sizing algorithms) interact but in a way that is not easily quantifiable when weight allometric models with implicit prediction error are used. In addition, allometric models should be reviewed when applied to other apple cultivars, fruit development stages or even for different fruit growth conditions depending on canopy management.

Modeling Wind Adjustment Factor for a prescribed burn plan. An application to Mediterranean stands in Southern Europe

Wind speed, which is significantly affected by terrain and vegetation, is one of the most crucial factors in terms of fire spread. Fire simulators compute wind speed as open 10-m wind speed multiplied by the Wind Adjustment Factor (WAF). In forested sites, the sub-canopy wind speed plays a fundamental role in low intensity fire or prescribed burn, and therefore, in prescribed burn plan. This research aims to estimate a WAF model based on in-stand wind speed at 2-m above ground and forest characteristics. We use Chi-square Automatic Interaction Detection to classify WAF according to the most influential stand variables.Fifty-seven sampling sites were established for WAF training and testing. WAF ranged from 0.03 to 0.84, showing significant differences due to stand characteristics. Our findings showed that canopy cover is the variable with the greatest influence on WAF. On the one hand, the non-linear WAF model reached a coefficient of determination (R2) of 90 %. On the other hand, a decision tree performed four decision nodes based on canopy cover, stand height, and stand density. These approaches propose a novel method to the identification of WAF for fuel treatment and prescribed burning implementation, avoiding the errors that could be generated using fixed WAF for each fuel model. The proposed model can be used to simulate the effect of different canopy management alternatives, both fuel treatments and timber harvesting, in wind speed at 2-m height.

Wood age, rootstocks and cultivars drive the formation of productivity and fruit size in sweet cherry

To maintain the high yields and fruit quality necessary for profitability of sweet cherry production, it is important to consider precision crop load and canopy management techniques during limb renewal. The effects of branch section age, rootstock, and cultivar on spur and flower density and fruit quality have been discussed in previous studies, but most of them focus on a limited range of fruiting wood ages and scion-rootstock combinations. This study aims to analyse the processes of sweet cherry productivity and fruit size formation on a wide range of wood age to determine the limit after which branch preservation is not sustainable, and to evaluate the influence of rootstocks and cultivars on these parameters. The results indicate that wood age is one of the main drivers of productivity formation in cherry. The highest flower density was observed on 3-year-old branch sections – 324 flowers per linear m, due to high spur density, number of reproductive buds per spur and flowers per bud. Productivity on 2-year-old wood was also good (256 flowers per linear m), while a sharp decline in flower density was noted on 4- and 5-year-old wood. The largest fruits were formed on young branch sections, with a significant decline in fruit weight and diameter on 4- and 5-year-old sections. Rootstock vigour had a bigger effect on floral organ induction on 1-year-old shoots, than on spurs. Based on the results, it is advisable to regularly renew lateral branches older than 3 years to maintain high yield efficiency and fruit quality.

Leaf chlorophyll contents in some European pear cultivars grafted on different rootstocks and its relation with growth and yield

Aim of study: To investigate the effect of different combinations of pear rootstocks and cultivars on the contents of leaf photosynthetic pigments and their relation with some growth and yield characteristics. Area of study: Ondokuz Mayis University, Samsun, Türkiye, in two years, 2021 and 2022. Material and methods: The pear cultivars ‘Santa Maria’, ‘Williams’, and ‘Deveci’ were grafted on eight rootstocks: two quince clonal rootstocks (BA29 and QA), five pear clonal rootstocks (FOX9, FOX11, OH×F333, OH×F87, FAROLD40) and Pyrus communis L. seedlings. Growth and yield attributes were calculated and chlorophyll and carotenoid contents were determined by the spectrophotometric method, using 99.8% methanol solvent for chlorophyll (chl) extraction. Main results: Chl a/b in the case of rootstocks, chl a and total carotenoids in the cultivars were found statistically significant; the ratio chl a/b ranged 1.71-2.30 in the case of rootstocks; in the case of cultivars chl a ranged from 17.77 (cv. ‘Santa Maria’) to 19.88 (cv. ‘Deveci’) μg mL-1, and carotenoids ranged 0.21-0.95 μg mL-1. Under the main impact of cultivars, rootstocks and their combinations, a significant difference was seen in the growth and yield attributes. Research highlights: A negative correlation coefficient was observed between photosynthetic pigments and morphological characteristics; however, the correlation coefficient was positive for canopy volume and annual shoot growth. Canopy management, especially with the use of rootstocks and cultivars that result in weaker growth, is helpful for improving chlorophyll content and yield performances.

Delay in the Ripening of Wine Grapes: Effects of Specific Phytotechnical Methods on Harvest Parameters

Due to climate change, the sugar content of grapes in Hungary has increased to such an extent that the high alcohol content alone can make wines disharmonious. In most vintages, this phenomenon is only a problem for early-ripening varieties. In order to prevent and treat this difficulty, we have carried out experiments in grape canopy management for four years with the aim of delaying ripening and thus reducing the sugar content of the grapes. The experiments were set up on an early (Pinot noir) and a late (Welshriesling) variety; two treatments (leaf removal—LR and short topping—ST) were applied and compared to untreated controls in the years 2019–2022. Our results showed that grape juice sugar yield was significantly reduced in all four years and for both cultivars, while the other measured parameters (yield, acidity, pH, and Botrytis infection) were only lightly affected.

UV-B Radiation Induced the Changes in the Amount of Amino Acids, Phenolics and Aroma Compounds in Vitis vinifera cv. Pinot Noir Berry under Field Conditions.

High UV-B radiation can challenge Pinot noir growth in the wine-making region of the Southern Hemisphere. The aim of this work was to determine UV-B effects on amino acids, phenolic composition and aroma compounds of Pinot noir fruit. Sunlight exposure with or without UV-B did not affect fruit production capacity, °Brix and total amino acids in the vineyard over the two years. This research reported increased contents of skin anthocyanin and skin total phenolics in berry skins under UV-B. The research showed that there were no changes in C6 compounds. Some monoterpenes concentrations were decreased by UV-B. The information also indicated how important leaf canopy management was for vineyard management. Therefore, UV radiation potentially affected fruit ripeness and crop load, and even stimulated the accumulation of phenolic compounds that may affect Pinot noir quality. This research reported that canopy management (UV-B exposure) may be a good way for vineyard management to increase the accumulation of anthocyanins and tannins in berry skins.

Effect of viticultural practices on yield and volatile composition of ‘Cabernet Sauvignon’ grapes

‘Cabernet Sauvignon’ is a vigorous grapevine that develops herbaceous aromas in grapes. Canopy management practices can impact grapevine physiology, and as consequence the photosynthesis, fruit yield, and grape composition, and improve the quality of the fruit. Leaf removals and apical leaf removals on grapevines have been shown to reduce herbaceous aromas. However, little is known, about the effect of the use of girdling on the concentration of volatile compounds in grapes. Thus, the objective of this study was to evaluate the effect of basal leaf removal (BLR), girdling, and girdling plus cutting the apical regions of the canopy (girdling + CAC), on the concentration of volatile compounds of ‘Cabernet Sauvignon’ grapes. Fruit yield, chemical composition, and volatile compounds were analysed in all treatments. Girdling + CAC showed a reduction in grape yield, and total acidity, however, increases in total soluble solids, and fruity aromas were observed in comparison to BLR and the control (no-canopy treatment). Controls showed the highest concentration of volatile compounds related to herbaceous and unripe fruit characteristics aromas. On the other hand, BLR showed increases in volatile compounds in the grapes related to floral character. These results suggest that grapevine canopy management modifies the chemical composition of ‘Cabernet Sauvignon’ grapes, and girdling techniques and increase the fruity aromas.

Rapid Adaptation of Chimonobambusa opienensis Leaves to Crown-Thinning in Giant Panda Ecological Corridor, Niba Mountain.

Leaf traits reflect the ecological strategy in heterogeneous contexts and are widely used to explore the adaption of plant species to environmental change. However, the knowledge of short-term effect of canopy management on understorey plant leaf traits is still limited. Here, we studied the short-term effect of crown-thinning on the leaf morphological traits of bamboo (Chimonobambusa opienensis), an important understorey plant and staple food for the giant panda (Ailuropoda melanoleuca) of Niba Mountain. Our treatments were two crown-thinnings (spruce plantation, CS, and deciduous broad-leaved forest, CB) and two controls (broad-leaved forest canopy, FC, and the bamboo grove of clearcutting, BC). The results showed that: the CS enhanced the annual leaf length, width, area, and thickness, CB decreased almost all annual leaf traits, and perennial leaf traits in CS and CB were the opposite. The log-transformed allometric relationships of length vs. width, biomass vs. area were significantly positive while those of specific leaf area vs. thickness were significantly negative, which varied largely in treatments and age. The leaf traits and allometric relationships suggested that the CS created a more suitable habitat for bamboo growth. This study highlighted that the understorey bamboo leaf traits could adapt the improved light environment induced by crown-thinning rapidly.