[PDF] Effects Of Trellising Shoot Positioning And Leaf Removal On Canopy Characteristics Microclimate Yield And Fruit Composition Of Chenin Blanc Grapevines eBook

Author : Joey D. Ratliff-Peacock
Publisher :
Page : 222 pages
File Size : 47,29 MB
Release : 1999
Category : Grapes
ISBN :

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Five trellis types were compared during 1996 and 1997 for their effect on Pinot noir yield components, fruit composition, fruit set, shoot morphology, leaf gas exchange, and trunk carbohydrate storage. These trellis systems were: upright vertical, cane pruned (double Guyot); upright vertical, spur pruned (bilateral cordon); Scott Henry, cane pruned; Lyre, cane pruned; and Geneva Double Curtain (GDC), cane pruned. In 1996, the double canopy systems had almost double the yield of the single canopy systems. There were no differences in yield or its components in 1997 among the five trellis systems. The bilateral cordon had a higher leaf area index than did the other systems. There were no differences in juice soluble solids, pH, or titratable acidity (TA) among the different trellis systems in either year. Also, there were no differences seen between the two canopies of the double canopy trellis systems in either year. There were no differences in sugar or starch concentrations in the trunk wood among the five trellis systems at any sample date. Sugar concentration in the trunk was highest during leaf fall and lowest at bloom on a dry weight basis. Starch concentration in the trunk was highest during dormancy and lowest during leaf fall and bud burst. Trunk volume was highest in the GDC and lowest in the Guyot. There was a negative correlation between most yield components and the carbohydrate concentration at bud burst. Leaf photosynthesis was strongly correlated with berry weight and skin anthocyanin content. In a separate study, yield components, fruit composition and wine quality of fruit generated in both curtains of the Scott Henry system were analyzed. In 1996, the bottom canopy had higher yield, cluster weight, more clusters per shoot and a higher TA than did the top canopy. Must soluble solids were not affected by vine canopy or sun orientation in 1996, but pH was lower and TA was higher in the bottom canopy. In 1997 the top canopy had a higher yield than did the bottom canopy. There were no canopy or orientation effects on leaf gas exchange, leaf area, shoot diameter, or intemode length. Wine from the top canopy was found to have more red color than wine from the bottom canopy.

Author : Xinyi Zhang
Publisher :
Page : 104 pages
File Size : 20,73 MB
Release : 2013
Category : Grapes
ISBN :

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Norton (Vitis aestivalis Michx) is a vigorous grape cultivar that grows a dense canopy. This leads to shade in the fruiting zone that negatively affects fruit quality. Canopy management is thought to reduce canopy density and overcome this negative effect. Shoot thinning, shoot positioning, leaf removal, and summer lateral removal were done in various combinations of five treatments. Three of the treatments with opened canopies increased light and ventilation in the fruiting zone. Total fruit weight per vine and average cluster weight were not affected. Neither were juice soluble solids, pH, potassium, and malic acid. Cane pruning weight per vine was not consistently altered by treatment. Titratable acidity of juice was affected, showing a decrease with leaf or leaf and summer lateral removal. These practices would be beneficial in growing Norton because of its potential for high acidity at harvest. Wine pH, titratable acidity, and potassium were not affected; however, all were acceptable in the finished wine. Visual observation showed that the dense canopy control was prone to rot, and the leaf and summer lateral removal treatment was prone to fruit sunburn. Leaf removal is likely a better choice than both leaf and summer lateral removal. Leaf removal is faster to implement and there is less potential for fruit sunburn from excessive defoliation that comes from both leaf and summer lateral removal.

Author : Alejandra Navarrete
Publisher :
Page : 100 pages
File Size : 12,55 MB
Release : 2015
Category : Grapes
ISBN :

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Vertically shoot positioned (VSP) training systems are common in Oregon's Willamette Valley, where deep fertile soils and high regional precipitation task growers with curbing vegetative vigor within this system. Management strategies, such as canopy hedging and cluster-zone leaf removal, are used to improve microclimate within the canopy and around the fruit. These cultural practices employed in commercial vineyards make it difficult to quantify canopy architecture and vine growth using currently established methods. Given the importance of vine leaf surface area to productivity of the vine, a study was conducted to determine how to best quantify leaf area in the highly managed VSP canopies. A regression model was developed from various linear leaf measures compared to leaf area measures on primary and lateral leaves of Pinot noir vines in the north Willamette Valley of Oregon. Maximum leaf length, maximum leaf width, mid-vein length and the distance between the central and interior lateral lobe tips were positively associated with total leaf area. Leaf width at the petiole junction was not a suitable measure. A second study was conducted to evaluate methods for quantifying vine leaf area and leaf distribution in moderate and high vigor VSP canopies, where dense foliage and interlacing shoots and tendrils can make vine measurements difficult. Traditional point quadrat analysis, digital photography, and a template leaf area method were compared to leaf areas determined by destructive sampling. Results show that point quadrat analysis severely overestimated the number of shaded canopy leaves in dense VSP systems. Results from the digital photography pixel recognition program correlated green pixels with leaf exposure but was not in good agreement with exterior canopy leaf area. The template leaf area method results confirm that it can accurately estimate total vine leaf area. The third study was developed to integrate these canopy quantification techniques with understanding how the leaf area: yield relationship affects fruit composition at harvest in cool climate Pinot noir grapes. A range of leaf area to yield ratios was created by cluster thinning vines to two crop levels. The study was replicated across four commercial vineyards with varying levels of moderate and high vigor. Results indicate that crop thinning had no impact on canopy leaf area, and there was limited impact of yield on fruit composition over two seasons. The studies included herein aimed to develop and evaluate methods for estimating leaf area within VSP-trained canopies in the Willamette Valley. Results of this work will provide improved methods by which viticulture researchers and whole-plant physiologists can employ to determine leaf area as a measure of vine productivity, and better understanding of source-sink relationships in managed canopies.