Grape Yield Research Articles

Nanotechnology: recent advances in viticulture and enology

Nowadays, nanoscience is a leading modern science that has a major impact on the food, pharmaceutical, and agriculture sectors. Several nanomaterials show a great potential for use during vine growing and winemaking processes. In viticulture, nanotechnology can be applied to protect vines against phytopathogens and to improve grape yield and quality. Thus, nanotechnology may allow the use of lesser amounts of phytochemical compounds, reducing environmental impact and promoting a more sustainable agriculture. And in winemaking, nanomaterials and nanodevices can be used to control the growth of spoilage microorganisms and to reduce or remove undesirable compounds, such as ethyl phenols (4-ethylphenol and 4-ethylguaiacol), biogenic amines, and tartaric acid, and so on, as well as to facilitate some technological processes (i.e. in wine filtration to eliminate microorganisms). This review summarizes recent studies with applications of nanotechnology in viticulture in order to facilitate agronomic management and optimize grape production and in enology to improve wine quality and safety. © 2021 Society of Chemical Industry.

Climate Change Adaptation in the British Columbia Wine Industry Can Carbon Sequestration Technology Lower the BC Wine Industry’s Greenhouse Gas Emissions?

This paper measures the benefits and costs of using biochar, a carbon sequestration technology in the British Columbia (BC) wine industry. It was found that the use of biochar, produced from wine industry waste, can reduce greenhouse gas emissions, and make a significant economic contribution to the BC wine industry. An economic model was developed to calculate the value-added from each of the three sectors that comprise the BC Wine industry value chain. The model uses biochar, produced from grape prunings and pomace, as a soil amendment in the vineyards. Grapes produced from these vineyards are used to produce wine. The assumptions for each variable used in this study are drawn from the literature and prior research by the authors. In addition to achieving the industry’s sustainability goals, each sector of the wine value chain is potentially profitable, however producing biochar as a profitable independent business is likely minimal compared to what could be achieved along the value chain with increased yields of the same quality. Biochar as a soil amendment is a long-term investment for farmers with results best assessed after multiple years. Future research is needed to better understand the biochar production process as an integral part of the BC wine industry, the carbon sequestration benefits, the specific increases in long-term grape yields and wine production. Also, the industry willingness to re-evaluate and change present industry practices, and other important benefits that can be derived from marketing climate friendly wine to BC consumers needs to be understood.

Proper deficit irrigation applied at various stages of growth can maintain yield and improve the comprehensive fruit quality and economic return of table grapes grown in greenhouses*

AbstractIn order to investigate the quantitative response of yield, fruit quality and economic return of table grapes grown in greenhouses under deficit irrigation applied at various growth stages, experiments were conducted in 2017 and 2018. Three irrigation levels (full irrigation, 2/3 and 1/3‐full irrigation) were applied at the fruit setting–swelling (stage 2), veraison (stage 4) and whole growth stages. The comprehensive fruit quality index (Qc) was determined in order to evaluate the overall quality of the berries and its effect on economic return. The results showed that deficit irrigation significantly decreased evapotranspiration (ET) and yield, and improved water use efficiency (WUE), individual quality parameters and Qc. Fruit quality was more sensitive to water deficit at stage 4 than at stage 2. Significant linear functions were found between a relative decrease in yield, berry quality parameters, Qc and a relative seasonal ET deficit. Net income under deficit irrigation was related to the price proportional coefficient (R). Higher net income was mainly determined by a higher yield when R was less than 1, while higher net income was determined by a higher Qc when R was greater than 3. An appropriate water deficit level at stages 2 and 4 (F2/3V2/3) is recommended as an optimal treatment as it produces a higher Qc, the highest WUE and net income without a significant decrease in yield.

Effects of Kaolin Treatment on Table Grape Characteristics of cv. Trakya Ilkeren (V. vinifera L.)

In this study, the effects of foliar kaolin particle film treatment (PF) on some table grape quality characteristics of cv. Trakya Ilkeren grown in Ankara conditions were investigated. The application of kaolin particle film (3%) was started just after fruit set. Treatments were repeated weekly for three weeks. Yield per vine was found to be 3.60 kg in Control (C) and 3.93 kg in PF treatment. No significant effect of PF treatment on grape yield was determined. TSS and maturity index were affected positively by PF treatment. TSS was determined as 19.45oBx and 20.68oBx in C and PF treatment respectively. The maturity index (%) increased from 30.30 (C) to 35.28 (PF) due to the increase in TSS. No differences in pH and titratable acidity were observed between PF and C. While cluster weight increased from 314.48 g (C) to 357.47 g (PF), cluster length increased from 17.14 cm (C) to 19.02 cm (PF). No significant change in cluster width, berry weight, width, length and berry firmness were determined. More intense skin color was obtained from PF treatment according to CIRG index. Considering the findings, it was concluded that PF treatment led to the development in quality attributes of cv. Trakya Ilkeren grown under high solar radiation and temperature stress.

Statement of Boron application impact on yield, composition and structural properties in Merlot grapes

Boron has been described as essential micronutrient for the development of some plants, including the vine. The objective of this study was to determine whether different applications of boron directly to bunches had any effect on vineyard productivity, chemical composition and on grape physical properties. The results obtained after two years trial indicated that boron sprays increased the productive parameters of the vineyard. Application of boron directly to the grape bunches proved to be effective in the absorption of this micronutrient by the vine, increasing the boron content in the grapes treated with different concentrations. In addition, boron-treated grapes have a higher concentration of organic acids and better cell wall definition than control sample grapes. The exogenous application of this micronutrient, as a complement to agricultural treatments, can be an interesting strategy to increase vine productivity and grape quality.

Evaluation of powdery mildew resistance of a diverse set of grape cultivars and testing the association between powdery mildew resistance and PR gene expression

Powdery mildew caused by the fungal pathogen Erysiphe necator is a global disease that reduces yield and quality in grapes (Vitis vinifera L.). Most grape cultivars are susceptible to this pathogen and thus the selection of powdery mildew resistant cultivars is a major objective of grape breeding programs. In this study, we evaluated powdery mildew resistance of a diverse set of 28 commonly cultivated local and international V. Vinifera cultivars after artificial inoculations with Erysiphe necator. Of these, 7 cultivars were found to be resistant while 10 and 11, were found to be moderately resistant and susceptible to powdery mildew, respectively. We also analyzed pathogen-responsive expression profiles of two defense genes, VvPR1 and VvGLP3 encoding a pathogenesis-related protein 1 homolog and a Germin-Like protein, respectively, in the same cultivars by qRT-PCR to determine whether defense gene expression is correlated with powdery mildew resistance. There was no significant correlation between powdery mildew ratings and induction patterns of these two defense genes. However, a significant correlation was found between VvPR1 and VvGLP3 expression only in cultivars that showed increased powdery mildew resistance. In addition, the grape cultivars we analyzed differed by berry ripening times, were shown to influence disease resistance. However, no significant correlation was found between powdery mildew ratings and the ripening times. Although potential mechanisms of powdery mildew resistance or susceptibility remain unclear, powdery mildew resistant grape cultivars identified here will be useful for growers and breeders interested in using these lines as parents in grape breeding programs.

Effect of grape yield and maceration time on phenolic composition of ‘Fetească neagră’ organic wine

The phenolic composition of wine is mostly determined by the accumulation of the phenolic compounds in the grapes, as well as their extraction into wine. To increase their concentration in grapes, yield reduction is usually performed by pruning, while to increase the extraction in wines, the maceration on skins is extended for longer periods of time. The present study focuses on the possibilities to apply both strategies to improve the polyphenol composition of organic red wines of Romanian variety ‘Fetească neagră’, which stands to benefit more from technological interventions than other varieties, which naturally accumulate higher phenol concentrations in the grapes. In the vineyard three experimental pruning variants were made, with 20, 28 and 36 buds/vine, while for wine, maceration was performed for either 8 or 16 days for each grape variant. The phenolic profiles of wines were determined by HPLC methods. The main anthocyanidins, such as malvidin, petunidin, delphinidin, peonidin and cyanidin, as well as the acylated and coumaroylated derivatives of malvidin and peonidin were quantitatively determined. Some other phenolic compounds, of various classes, such as gallic, p-benzoic, p-coumaric and ferulic acid, catechin, epicatechin, myricetin, quercetin and trans-resveratrol were also determined. The quality of the organic ‘Fetească neagră’ wines depended highly on the vintage, but yield reduction and the extension of skin maceration duration were especially beneficial in the less favourable year, when classical technologies lead to less accumulation of sugars, colour and other polyphenols. Concomitant application of both strategies led to the best results, irrespective of the year.

INFLUENCE OF SHAPE FORM ON YIELD AND QUALITY OF GRAPES OF KUNLEAN AND PERVENETS MAGARACHА VARIETIES

The research was carried out in 2009, 2010, 2017, 2018 on the grape plantations of the experimental site of the Novocherkassk branch of the All-Russian Research Institute for Viticulture and Winemaking (Novocherkassk, Rostov region). In the vineyard of the Kunlean variety (rootstock Kober 5BB), planted in 2003 according to the 3x1.5 m scheme, the experiment provided for two options with bush shapes: a two-sided horizontal cordon and a two-sided horizontal cordon with a ground sleeve and a recovery knot. On the root-related plantings of grapes tolerant to phylloxera of the Pervenets Magaracha variety, planted in 1986 according to the same scheme, the forms of the bush were studied: a two-sided horizontal cordon, a long-sleeve and a two-sided horizontal cordon with a ground sleeve and a recovery knot. The load of shoots in all variants for both varieties was the same — 40 shoots per bush. The purpose of the research was a comparative analysis of the fruitfulness, yield and quality of grapes, depending on the shape of the bush. As a result of many years of research, it was revealed: on the Pervenets Magaracha variety, the highest rates of fertility (the share of fruit-bearing shoots is 82 %, K 1 — 1.45) and yield (14.0 t/ha) were in plantings with the form of bushes-a two-sided horizontal cordon with a ground sleeve and a recovery knot. The quality of the grapes was approximately equal in the variants with a long-sleeve and shaping and a two-sided horizontal cordon with a ground sleeve. The data on the annual growth of shoots were the lowest in the variant with a single-arm stem shape (shoot volume of 7.9 cm 3 , maturation of 44 %). On the Kunlean variety, the highest parameters of fruitfulness (the share of fruit — bearing shoots is 85 %, K 1 — 1.80), yield (27.0 t/ha) and the quality of berry juice (230 sugars and 7.8 g/cm 3 titrated acids) were in plantings with the form of bushes-a two-sided horizontal cordon with a ground sleeve. Data on the annual growth of shoots were also higher in this variant (shoot volume 35.0 cm 3 , aging 68 %).

Grape production assessment using surface and subsurface drip irrigation methods

The study involved experimental work implemented from April 2014 until March 2017. Its purpose was to observe grape production quality parameters, such as yield, water productivity, berry size and bio-mass. Different irrigation methods, such as drip irrigation (DI), drip irrigation with plastic mulching (DIPM), drip irrigation with organic mulching (DIOM), subsur-face irrigation with stone column (SISC), subsurface irrigation with mud pot (SIMP), and subsurface irrigation with plastic bottles (SIPB) have been used during the experimental work. The crop has been irrigated following the CROPWAT-8.0 model developed by the FAO. Climate parameters are obtained from the automatic weather station located near the experi-mental field. Based on experimental results and analyses, it has been observed that the drip irrigation with the plastic mulching method is the best for irrigation in terms of the grape yield comparing with all other methods due to its highest productivity of 35–40%. Subsurface irrigation with the plastic bottle method is found to be suitable as it gives 20% higher yield than the traditional drip irrigation method. The SIPB method shows the cost-benefit ratio of 112.3, whereas the DIPM method had the ratio of 36.6. Based on the cost-benefit analysis, it is concluded that the SIPB method is economically more viable as compared with all other methods. Hence, based on the findings, it is recommended to use drip irrigation with a plastic mulch-ing and drip irrigation with a plastic bottle as the best options to achieve grape productivity while using minimum water.

Ethephon‐induced leaf senescence increases the concentration of yeast‐assimilable nitrogen in grape must (Vitis viniferacv. Riesling)

Background and Aims Leaf senescence induces a massive shift of the nitrogen (N) allocation within plants, but its influence on the storage of yeast-assimilable N (YAN) in grapevine berries is unclear. The aim of this work was to investigate whether the YAN concentration in grape must can be increased by a targeted induction of leaf senescence. Methods and Results Leaf senescence was induced in two consecutive seasons by an ethephon treatment of grapevines (Vitis vinifera cv. Riesling) before harvest, and its effect on the amino acid and ammonium balance of berries and must, as well as on alcoholic fermentation performance was investigated. The ethephon-induced senescence caused a significant increase in YAN concentration in berries and must, based on a general increase in most amino acids. Compared to natural senescence, the ethephon treatment led to a lower proline : arginine ratio, a lower sugar concentration in the must and a lower grape yield. Conclusions Ethephon-induced leaf senescence enhances the nutritional value of grapes and improves the fermentability of grape must. Significance of the Study Our results enable wine producers to improve the nitrogen use efficiency of vines and to ensure a balanced N nutrition of the yeast.

Improved agricultural Water management in data-scarce semi-arid watersheds: Value of integrating remotely sensed leaf area index in hydrological modeling

In watersheds located in semi-arid regions, vegetation dynamics, evapotranspiration (ET), and associated water and energy balances collectively play a major role in controlling hydrological regimes and crop yield. As such, it is challenging to predict the complex hydrological processes and biophysical dynamics. This challenge increases in areas with limited data availability. The key objective of this study was to evaluate the direct integration of remotely sensed Leaf Area Index (LAI) data into a hydrological model to improve streamflow, ET, and crop yield estimates. We also demonstrated how an improved model integrated with remotely sensed LAI data can inform water managers by predicting water productivity (WP) under different irrigation schemes. We took agricultural-dominated San Joaquin Watershed in California, United States, as our testbed and integrated the Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m resolution 4-day total LAI data into the SWAT (Soil and Water Assessment Tool) model. Results showed that, compared to conventional SWAT model that relies on semi-empirical equations and user inputs for simulating biophysical processes, direct LAI integration into SWAT model (SWAT-LAI) notably captured the actual vegetation dynamics and improved ET and crop yield estimations. The WP simulated by the improved SWAT-LAI model for almond and grape yields varied within a range from 0.363 to 3.81 kg/m3 and 0.32 to 4.76 kg/m3 across different irrigation applications. The outcomes of this study showed that deficit irrigation application could be a viable option in water stressed regions, since it can save a substantial amount of irrigation water and maintain the higher water productivity required for both almond and grape yield production. This study shows an evidence of how remotely sensed data integrated into hydrological models can serve as a decision support tool by providing quantitative information on crop water use and crop production.

Response of Tannat (<i>Vitis vinifera</i> L.) to pre-flowering leaf removal in a humid climate

The aim of this study was to test the effect of pre-flowering leaf removal (PFD) on grape sanitary status, yield, source-sink balance and berry composition. A completely random block design experiment was conducted over four seasons in a commercial vineyard of the Tannat/SO4 combination located in the south of Uruguay (34° 35´30 S, 56° 15´23 O). The PFD treatment was compared with a commercial defoliation (CC) comprising partial leaf removal between the fruit set and cluster closure stages (four leaves from the first node), a traditional practice carried out by winegrowers. Both treatments received equal phytosanitary management during the study. The results were conditioned by seasonal meteorological conditions, particularly rainfall, temperature and evapotranspiration. The seasonal effect was significant for yield components, berry composition and source-sink balance. The PFD treatment resulted in the lowest yields in all four years and modified the primary and secondary composition of berries. It also showed a higher anthocyanin potential in 2016, 2017 and 2019, related to a higher percentage of exposed clusters, lower yield and/or higher leaf to fruit ratio. In 2017, environmental conditions were more favourable for the development of bunch rot, and lower values of incidence (3 %) were recorded for the PFD treatment compared to CC (22 %), due to greater exposure of bunches and less compact bunches. The PFD vines showed a steady reduction in dry matter production capacity, mainly explained by the steady reduction in yields. The Tannat variety showed a differential response to PFD depending on the weather during the growth cycle. Under humid climate conditions, pre-flowering defoliation proved to be effective for yield control, by reducing bunch rot incidence, and for improving some attributes in terms of grape composition. This work provides useful information for grape growers in humid regions on how to improve the sanitary status and quality of their production.

Effects of different nitrogen application rates on dry matter accumulation, distribution and yield of grape under alternate partial root-zone drip irrigation.

To get an optimal mode of irrigation and nitrogen supply for table grape production in North China, a pot experiment was conducted to investigate the effects of different irrigation modes and N application rates on dry matter accumulation and distribution, yield, water use efficiency, and nitrogen use efficiency of table grape. The irrigation modes included conventional drip irrigation (CDI, with sufficient irrigation), alternate partial root-zone drip irrigation (ADI, with 50% amount of the irrigation water of CDI) and fixed partial root-zone drip irrigation (FDI, with 50% amount of the irrigation water of CDI). The nitrogen application rates were set at 0.4 (N1), 0.8 (N2) and 1.2 (N3) g·kg-1 dry soil. The results showed that compared with CDI, ADI and FDI reduced new shoot pruning amount by 34.8% and 11.2%, respectively. New shoot pruning amount increased with increasing N application rates, being highest under CDIN3. Dry matter accumulation of ADI was the highest, being 5.1% and 12.8% higher than CDI and FDI. Dry matter accumulation was higher under N2 and N3 than N1. Compared with CDI and FDI, leaf to fruit ratio reduced but harvest index significantly increased in ADI, while those variables showed no significant difference among diffe-rent N application rates. The ratio of pruning amount to the biomass accumulated in the current year in ADIN2 was the lowest among the treatments. Compared with CDI and FDI, ADI increased grape fruit yield by 6.0% and 10.4%, respectively. Fruit yield was enhanced with increasing nitrogen application rates under the same irrigation condition, with the highest yield under the ADIN2 and ADIN3. Water use efficiency (WUE) increased significantly in ADI compared with CDI and FDI, with the highest value being observed in ADI coupled with N2 or N3. Nitrogen use efficiency (NUE) showed a trend of ADI＞CDI＞FDI. In addition, NUE decreased with increasing nitrogen supply level across the irrigation modes. In conclusion, ADIN2 could reduce the redundant growth of grape tree, promote the transfer of dry matter to fruit, which increased yield and use efficiency of both water and nitrogen, which is a suitable coupling water and nitrogen supply mode for grape production in northern China.

Novel herbal extract-Samved Fitocheck growth retardant for fruitfulness and yield of grapes

Chemicals that slow cell division and cell elongation in shoot tissues and regulate plant height physiologically without formative effects. So far only chemical growth retardants are available in market which have residue problem. So, to overcome residue issue Vasumitra Life Energies Pvt. Ltd has developed a formulation of herbal extract having role in induction of fruitfulness as well as retardation of unwanted shoot growth. The extract was applied to vineyard at Pandharpur, during the year 2018-19 at different concentrations keeping Chlormequat Chloride (CCC) as check and one control treatment replicated five times at 5, 7 and 15 leaf stages after foundation pruning as well as 3 leaf stage after fruit pruning. The results revealed that significantly reduced shoot length, internodal length and increases the cane thickness of grape vine. The SPAD values, number of bunches per vine, weight of bunch were found significantly higher in treatments with herbal extract as compared to CCC and control. Fitochek @ 2 ml/lit showed highest fruitfulness percentage 65%, and yield 16.46 t/acre. It had no significant influence on berry length, berry diameter, TSS and acidity. Fitochek and control had no residues at harvest while CCC have residue above EU MRLs. Furthermore, no phytotoxic effects on grape vine were observed in any of treatments under investigations. From the above result and literature surveyed this is first report to demonstrate this novel organic compound (Fitochek) can be used effectively @ 2 ml/lit at different stages (After Foundation and fruit pruning) to retard unwanted shoot growth as well as overcome the residue problem.

Effects of Several Preharvest Canopy Applications on Yield and Quality of Table Grapes (Vitis vinifera L.) Cv. Crimson Seedless.

Modern viticultural areas are being confronted with the negative impacts of global warming on yield and fruit composition, with especially adverse effects on anthocyanin synthesis. Novel and sustainable tools, such as biostimulants, may represent a viable alternative to traditional cultural practices, thus promoting eco-friendly strategies to enhance the yield, fruit quality and abiotic stress tolerance of grapevines. ‘Crimson Seedless’ is a late-season red table grape variety, and due to climatic warming, its berries are frequently failing to acquire the commercially acceptable red color. Canopy applications of different biostimulants, namely, Kelpak®, Sunred®, Cytolan®, LalVigne™ Mature as well as Ethrel® Top, were tested on grapevine cv. Crimson Seedless grown under semi-arid Mediterranean conditions in order to evaluate their effects on yield and fruit quality. Some of the products were sprayed in canopies at labeled doses, and some were applied at doses reported in other studies. For the control treatment, canopies were sprayed with water. Sampling started at veraison and was repeated at 10-day intervals to measure the evolution of berry weight, length and diameter, as well as the total soluble solids and titratable acidity of the juice. The grapes were harvested when the berries of one of the treatments attained the commercially acceptable color. The greatest improvements in the red berry color were achieved with Sunred® (at a dose of 4 L ha−1) and Ethrel® Top (250 ppm plus glycerol at 1%), each applied at veraison and 10 days later. The different applications had varying effects on productivity and qualitative parameters. Only Sunred® improved the accumulation of anthocyanin and the overall acceptability of table grapes by consumers. The obtained results clearly demonstrate that applying Sunred® can improve the yield and qualitative parameters of the red table grape variety ‘Crimson Seedless’, indicating that this biostimulant could be a viable alternative to the most widely used plant growth regulator, ethephon.

Wood-based biochar for small fruit production in southern Quebec, Canada

The market for small fruits (grapes, blueberries, strawberries, and raspberries) is valued at more than $100 million CAD per year in Quebec, Canada. Wood-based biochar is an amendment that improves soil quality, which may boost small fruit growth and production. The objective of this research was to determine if wood-based biochar could increase the yield and quality of grape, blueberry, strawberry, and raspberry in southern Quebec. We evaluated the fruit yield as well as the quality parameters like average fruit weight, fruit firmness, color, juice pH, total soluble solids, total phenolic content, and antioxidant activity. Field trials were established on commercial farms with grape, blueberry, strawberry, and raspberry production systems in plots that received wood-based biochar and no biochar in spring (April–May). Small fruits were harvested at their ripening stage for yield and quality evaluation in the fall (July–October). Biochar application did not improve yield and quality parameters of small fruits, except it gave a marginally higher yield of grape (3.7 vs. 4.4 t·ha−1, P = 0.08) and a higher average fruit weight of strawberry (11.9 vs. 13.2 g, P < 0.05). There was no difference in the quality of the fruit from biochar-amended and control plots in the first year of biochar application, possibly because the quality parameters are affected more by weather conditions, handling, and storage than by soil quality. This work suggests that wood-based biochar (<5 t·ha−1) has a limited first-year impact on small fruit yield and quality in southern Quebec, Canada.

Effects of organic and organomineral fertilizers on yield, quality and plant nutrition in Prima grape variety

Organik ve organomineral sıvı gübrelerin, alternatif bitki besleme ürünleri olarak bahçe bitkilerinde kullanımı zamanla yaygınlaşmaktadır. Bu nedenle gübrelerin bağcılık bölgeleri için önemli yeni bazı üzüm çeşitlerinde etkilerinin denenmesinin faydalı olacağı düşünülmüştür. Bu araştırma, Prima üzüm çeşidinde yürütülmüştür. Çalışmada, yapraktan ve topraktan organik (BioGas, sırasıyla 400 cc 100 L-1 ve 4 L da-1) ve organomineral (AminoSEL-K, sırasıyla 300 cc 100 L-1 ve 4 L da-1), gübre uygulamalarının tek başına ve birlikte uygulanmasının etkilerine bakılmıştır. Araştırma sonucunda en yüksek verim, salkım ağırlığı, büyüklüğü ve suda çözünebilir kuru madde değerlerinin (sırasıyla 9251 g omca-1, 462.6 g ve %15.58) organomineral uygulamasında olduğu belirlenmiştir. Organik+organomineral uygulaması tane büyüklüğünü ayrı ayrı ve birlikte uygulandığında kontrol uygulamasına göre artırmıştır. Topraktan uygulamanın salkım ve tane büyüklüğünü artırdığı saptanmıştır. Topraktan ve yapraktan uygulama şekli toprak ve yaprağın besin maddesi kapsamında önemli farklılık oluşturmamıştır. Organik+organomineral gübre uygulamasında toprakta potasyum; yalnız organik uygulamasında toprakta magnezyum, demir, çinko ve bakır konsantrasyonları yüksek bulunmuştur. Sonuçta, Prima çeşidinde farklı gübre ve uygulama şekli uygulamalarının incelenen özelliklere göre farklı etkide bulunduğu saptanmıştır. Ancak, bu gübrelerin etkisi konusunda kesin yargıya varılabilmesi için çalışmanın izleyen yıllarda da sürdürülmesinin uygun olacağı kanısına varılmıştır.

Influence of crop regulations on growth, yield and quality of grapes (Vitis vinifera) in North-East India

Influence of crop regulations on growth, yield and quality of grapes (Vitis vinifera) in North-East India

Soil and Regulated Deficit Irrigation Affect Growth, Yield and Quality of 'Nero d'Avola' Grapes in a Semi-Arid Environment.

The present work studied the effect of two consecutive years of regulated deficit irrigation (RDI) compared to rain fed management on the vegetative growth, yield, and quality of ‘Nero d’Avola’ grapes. The trial was conducted separately in two soils (vertisol and entisol) located at the top and bottom hillside of the same vineyard. Vertisol was characterized by greater depth, organic matter, exchangeable K2O, and total N than entisol. RDI was based on an irrigation volume at 25% of estimated crop evapotranspiration (ETc) up to end of veraison and 10% of estimated ETc up to 15 days before harvest. Predawn water potential (PDWP) was used as indicator of plant water status and irrigation timing. No difference in irrigation management was evident between vertisol and entisol. Under Mediterranean climate conditions, RDI was able to enhance grape yield and vegetative growth, especially in vertisol, but it reduced berry titratable acidity and total anthocyanins. ‘Nero d’Avola’ showed to adapt to drought conditions in the open field. Both soil type and irrigation regimes may provide opportunities to obtain different ‘Nero d’Avola’ wine quality and boost typicality.

Occluded Grape Cluster Detection and Vine Canopy Visualisation Using an Ultrasonic Phased Array.

Grape yield estimation has traditionally been performed using manual techniques. However, these tend to be labour intensive and can be inaccurate. Computer vision techniques have therefore been developed for automated grape yield estimation. However, errors occur when grapes are occluded by leaves, other bunches, etc. Synthetic aperture radar has been investigated to allow imaging through leaves to detect occluded grapes. However, such equipment can be expensive. This paper investigates the potential for using ultrasound to image through leaves and identify occluded grapes. A highly directional low frequency ultrasonic array composed of ultrasonic air-coupled transducers and microphones is used to image grapes through leaves. A fan is used to help differentiate between ultrasonic reflections from grapes and leaves. Improved resolution and detail are achieved with chirp excitation waveforms and near-field focusing of the array. The overestimation in grape volume estimation using ultrasound reduced from 222% to 112% compared to the 3D scan obtained using photogrammetry or from 56% to 2.5% compared to a convex hull of this 3D scan. This also has the added benefit of producing more accurate canopy volume estimations which are important for common precision viticulture management processes such as variable rate applications.