1,720,963 research outputs found
Effects of early shading and defoliation on bunch compactness, yield components, and berry composition of Aglianico grapevines under warm climate conditions
No full textPrebloom leaf removal is a canopy management practice used in viticulture to decrease bunch compactness at harvest. However, this practice may not be suitable in dry and warm areas because it may expose bunches to excessive direct sunlight, undesirably decreasing titratable acidity and increasing the pH of berry juice. This study was designed to test the hypothesis that shading between preanthesis and fruit set may be used for Aglianico grapevines as an alternative strategy to decrease bunch compactness without removing leaves around the bunches. This treatment was also thought to maintain berry juice acidity at harvest. The following nine treatments were compared: two defoliations (50 and 90% leaf removal), five whole-canopy shadings (10, 30, 50, 75, and 90% reduction of ambient
light), one partial canopy shading (using a 30% shade net), and an unshaded and undefoliated control treatment. Fruit set, berry number per bunch, bunch weight, and yield per vine were significantly affected by several of these treatments. Bunch compactness was reduced only by shading in the range of 50 to 90%. Surprisingly, defoliation decreased fruit set but not bunch compactness because the defoliation caused shortening of the total length of the bunch axes. Berry composition was not negatively affected by 50 to 90% shading, whereas defoliations and 10 to 30% shading decreased titratable acidity and increased the pH of the berry juice at harvest. Flower number per bunch in 2010 decreased linearly with decreasing net photosynthesis per shoot measured in 2009 between prebloom and fruit set. The results of this study suggest that early shading may be an efficient alternative practice to decrease bunch compactness without any negative effect on berry juice composition at harvest
Influence of branch autonomy on fruit growth and quality in nectarine trees
No full textDifferent studies have reported that peach tree branches are characterized by partial autonomy for carbon budget. Most of the studies have focused their attention on fruit growth, whereas no information is available about the effect of branch autonomy on fruit composition. The aim of this experiment was to study how branch autonomy affects fruit size and quality in nectarine trees. The trial was conducted in 2008, in Eboli (Italy), on ‘Rose Diamond’ nectarine trees grafted on GF677. The experiment compared four thinning treatments: a control treatment (C) including trees that were commercially fruit-thinned; a flower-bud thinning treatment (BT) applied homogeneously in all the canopy; a bud-thinning treatment where all the flower-buds of the top half of the canopy were removed, whereas in the bottom canopy layer thinning was applied at fruit stage as in the C treatment (Top-BT); the fourth treatment was similar to Top-BT, with the differences that the bottom layer was completely flower-bud thinned and the top commercially fruit thinned (Bottom-BT). Crop load in each canopy layer was very
similar between treatments. BT treatment induced significant increments in fruit fresh weight at harvest in both canopy layers and in soluble solids content (SSC) only in the bottom layer compared to the C. Interestingly, fruit size (in both canopy layers) and SSC (only in the bottom canopy layer) was higher in Bottom-BT and Top-BT trees compared to BT trees. The a* coordinate of the fruit skin cover color decreased slightly in thinned trees compared to control. Skin ground color and flesh firmness were very similar in Bottom-BT, Top-BT, and C trees. These results suggest that branch autonomy is only partial and carbon can move along relatively short pathways from canopy layers where demand for carbon is lower to layers where the demand is higher. These effects depended on the measured parameters and the canopy layer
Harvest index for mechanically handled peach fruits in post-harvest
No full textThe aim of this study was to define harvest indexes, based on peach skin ground color, suitable to allow mechanical grading and reach at the same time high fruit quality. Two cultivars, Springbelle and Douceur, were included in this research. In the first year of the study, harvest was performed in three pickings, fruit samples were graded with a mechanical sizer, and divided into seven categories based on their ground skin color, measured with a colorimeter. On the same fruit, soluble solids content, titratable acidity, and flesh firmness were measured. Moreover, the evaluation of damage eventually caused by grading and organoleptic tests were performed. These data were used to define harvest indexes based on the a* coordinate of skin ground color. The harvest indexes obtained during the first year were used as harvest index in the second year of the trial to test their suitability. The results showed that the method can be used successfully depending on the cultivar. Indeed, the model seems to work better on Springbelle, whereas skin ground color did not correlate with the qualitative characteristics and the ripening level of Douceur
Variabilità intrachioma della temperatura, della fenologia della fioritura e della crescita dei frutti di pesco
No full textCompattezza del grappolo e caratteristiche quanti-qualitative della produzione di piante di Aglianico (Vitis vinifera L.) sottoposte ad ombreggiamento o defogliazione applicate in fioritura
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Influence of intensity of post-veraison defoliation or shoot trimming on vine physiology, yield components, berry and wine composition in Aglianico grapevines
No full textBackground and Aims: Post-veraison trimming and defoliation have been proposed as strategies to decrease the concentration of berry carbohydrate at harvest and of wine alcohol, but it is unclear which of these two pruning techniques is more suitable and at what intensity they should be applied. The aimof this 3-year study was to compare the suitability of two intensities of post-veraison trimming or defoliation in controlling sugar accumulation in the berries of Aglianico grapevines.
Methods and Results: Five treatments were compared: two intensities of defoliation, two intensities of shoot trimming and a control. All pruning treatments decreased berry TSS at harvest and wine alcohol concentration. Defoliation and trimming of moderate intensity also improved wine sensory score, whereas intense defoliation and trimming can affect negatively this parameter.
Conclusions: Post-veraison defoliation and trimming of moderate intensity appear to be suitable strategies for decreasing berry TSS at harvest and wine alcohol concentration.
Significance of the Study: The selection of the correct intensity of leaf removal appears to be one of the critical factors in correctly designing a suitable strategy of post-veraison summer pruning that aims to decrease sugar accumulation in the berries, whereas the choice of the type of pruning appears to be less crucial
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