To see the other types of publications on this topic, follow the link: Cluster thinning.
Dissertations / Theses on the topic 'Cluster thinning'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 15 dissertations / theses for your research on the topic 'Cluster thinning.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Mauritson, Cameron John. "The Fruiting and Berry-Chemistry Responses of Zinfandel Grapes to Cluster Thinning." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/60.
Full textAbstract:
A field experiment was conducted in the Rockpile appellation of Sonoma County during 2007 and 2008. The experimental design was a randomized complete block with five replicates. Zinfandel vines were subjected to three levels of cluster thinning during the lag phase of berry growth: vines were thinned to 2 clusters per shoot with shoulders retained if present (2CS), 1 cluster per shoot with shoulders retained if present (1CS), or 2 clusters per shoot with shoulders removed if present (2CNS).
Cluster thinning Zinfandel grapevines during lag phase led to reductions in yield and crop load and increased °Brix of the fruit. In both years, wines that were made from vines with the lowest crop load had consistently higher amounts of small and large polymeric pigments, tannins and total iron-reactive phenolics.
Cluster thinning vines to 2CNS at lag phase consistently decreased the number of berries per cluster and cluster weight. Thinning vines to 1CS resulted in fewer clusters per vine in 2008.
Botrytis bunch rot tends to develop between the shoulder or wing and the main cluster in certain varieties. Shoulder removal in areas with a high risk of Botrytis should conclusively determine if this thinning method helps to decrease disease incidence. Additional research is also recommended with other varieties to assess possible differences between shoulder thinning and removing entire clusters on berry composition, yield, subsequent wine composition and crop load.
2
Liggieri, Silvia. "Optimizing grape cluster exposure to increase desirable aroma compounds and decrease disease severity." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/87535.
Full textAbstract:
By increasing fruit exposure to sunlight and influencing fruit development, leaf thinning in the fruit zone can improve grape quality and lower disease incidence; however, further investigations on the timing, varietal response and intensity are needed to optimize results and to better understand underlying physiologic responses. Fruit zone leaf thinning was applied at different timing and intensities to evaluate its effect on cluster health and fruit composition in Cabernet Sauvignon and Chardonnay. Treatments consisted of control (C), pre-bloom leaf thinning (PB) and two levels of fruit-set leaf thinning (three leaves, PF3 and six leaves, PF6). In an additional project on Cabernet Sauvignon, two levels of hedging (17th node, NH and 12th node, H) were integrated with no leaf thinning (L) and fruit set leaf thinning (LR, three leaves).
All leaf thinning treatments consistently reduced disease incidence compared to control vines in both varieties, with the reduction extent varying between 2017 and 2018. Yield was not negatively affected by leaf thinning treatments, even though PB reduced cluster compactness by decreasing the number of berries per cluster of Chardonnay in 2017. Control vines tended to have greater titratable acidity than defoliated vines, while Brix and pH responses varied between seasons. No direct positive correlation was found between sunlight exposure and norisoprenoids concentration. Post fruit set leaf thinning PF6 consistently increase free norisoprenoids at harvest, while pre-bloom defoliation never did. Heterogeneous responses were observed for bound and total norisoprenoids. In Cabernet Sauvignon free, bound and total 1,1,6-trimethyl-1,2-dihydronaphtalene (TDN) was consistently increased by PF3. Hedging negatively influenced Brix and anthocyanins accumulation in 2017, and increased free norisoprenoids while decreasing the bound and total fraction. Results revealed that a high level of stress possiblt caused by excess sunlight and/or reduced photosynthesis might negatively affect norisoprenoids glycosylation.<br>Master of Science in Life Science
3
Grave, João Carlos Sousa de Barros. "Efeitos da desfolha e monda de cachos no rendimento e qualidade da uva e do vinho na casta Merlot." Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6171.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do Porto<br>This study was created with a purpose of searching for an effective method of promoting an higher concentration of colour compounds in the wine, on Merlot variety. We evaluated the effects of three different canopy management practices in the vineyard: early defoliation at pre-bloom (DF), partial defoliation at pea size (DN) and cluster thinning at veraison (M), compared with a control (T). The trial was conducted in 2012, in a company called Encosta do Sobral Sociedade Agrícola which is located near Tomar, inside Tejo wine region.
The weather conditions were unusual, that year, registering very little rainfall during the grapevine activity season, which makes it risky to extraplore results for future years.
The early leaf removal caused significant effects on canopy structure, by reducing leaf layer number and increasing cluster exposure.
Cluster thinning and early defoliation were both effective in reducing yield of 35,5% and 23,4% respectively.
The treatments that had sufered canopy management practices provided qualitative gains, which were recognized in analytical and sensory analysis, though they didn’t reach statistical significance
4
Fertel, Thomas Jerome. "CLUSTER THINNING EFFECTS ON METHOXYPYRAZINE, RESVERATROL AND BERRY CHEMISTRY IN VITIS VINIFERA CV. CABERNET SAUVIGNON." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/535.
Full textAbstract:
Cabernet sauvignon is the most widely planted red wine grape in California and is valued in the hundreds of millions of dollars. Cabernet sauvignon grapes, when severely vigorous or overcropped, can contain vegetal aromas and flavors when harvested. 3-alkyl-methoxypyrazines are the volatile compounds responsible for this effect and can lower the perceived quality of the wine. Resveratrol is a phytoalexin that has many medical and health benefits and can be found in red wines. An experiment was conducted in Paso Robles, CA to assess the effects of five yield levels, manipulated through cluster thinning, on methoxypyrazine and resveratrol concentrations. Berry weights and chemistry were also measured, in the form of ºBrix, pH, and TA. In 2009 and 2010, no significant statistical differences were found in methoxypyrazines in the harvested grapes. In 2009, resveratrol concentrations were below the detection limits in the wine produced. In 2010, berry weight and chemistry measurements were not significantly different, except for grapes from lightly- and greatly-thinned vines which varied in pH at harvest. The 2009 wines were subjected to discrimination and preference testing by trained tasters. No significant difference was found in the discrimination test and no difference was found using the Friedman and Kramer’s Rank test for the preference test. Only a very slight difference was found between the wines made from unthinned and greatly-thinned vines according to Tukey’s Multiple Comparison Test. The findings of this thesis suggest that cluster thinning does not affect methoxypyrazine and resveratrol concentrations or sensory analysis in Cabernet sauvignon grown on the east side of Paso Roble, CA.
5
Monteiro, Rui Miguel de Jesus. "Desfolha precoce na casta Aragonez." Master's thesis, ISA, 2014. http://hdl.handle.net/10400.5/6802.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências. Universidade do Porto<br>This study aimed to the influence of two techniques, early defoliation and cluster thinning, in the agronomic behavior of Aragonez, its effects on yield, health and quality of grapes.
The trial was conducted in 2013, on a vineyard of Quinta do Pinto, in Lisbon wine region, Portugal. The treatments studied were defoliation at flowering (ED), defoliation at the end of pea size and cluster thinning at verasion (D&T) and a non-defoliated and non-thinned treatment was used as a control.
The early defoliation consisted of the removal of 6 basal leaves from all shoots one week before flowering while D&T consisted of a defoliation of about 3 basal leaves only in the east side of the canopy at the end of pea size and bunch thinning of all second order clusters at veraison.
The early leaf removal caused significant changes in the structure of canopy, by reducing leaf area, the exposed leaf surface and increased cluster exposure, thus improving the microclimate covered. This improvement was reflected in the decrease of botrytis. This treatment also caused a decrease of 57 % in yield compared to the control, however no significant differences in the quality of the grapes to harvest.
6
Calhau, André Filipe Perdigão. "Efeitos da desfolha precoce e da monda de cachos no rendimento e qualidade de uvas e vinho na casta Cabernet Sauvignon." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4094.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia<br>This study tested two techniques: cluster thinning and early defoliation in order to determine their effectiveness in yield control and its effects on quality of grapes and wine of Cabernet Sauvignon. The trial was conducted in 2009, on a vineyard of Encosta do Sobral Agricultural Society, situated in the Tomar, a sub-region of Tejo wine region, Portugal. The treatments studied were cluster thinning at verasion, defoliation at flowering and control. The leaf removal caused a small fruit set reduction, but didn‟t induce a significant production loss, unlike cluster thinning that reduced it by 25%.
Leaf removal increased the total acidity and concentration of total polyphenols of grapes. Cluster thinning didn‟t affect the grape composition at harvest.
The wine from defoliation got the best overall qualification, followed by wine from cluster thinning, and finally the wine from control. In the trial conditions, and comparing the effects of both treatments (DF and M), it was found that early defoliation allowed the highest qualitative gains while not affecting the yield such as cluster thinning.
7
Pinto, Miguel Guerreiro Mestre Messias. "Efeito da época e intensidade de monda nas castas Aragonês e Alicante Bouschet." Master's thesis, ISA/UTL, 2013. http://hdl.handle.net/10400.5/5649.
Full textAbstract:
Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia<br>The quality of the grapes is changeable and through this study we pretend to analyze the effect of intensity and season of cluster’s thinning (M0 – control, M1 – thinning, leaving one cluster/ talon in buckshot berry season, M2 - thinning, leaving one cluster/talon in verasion season, M3 - thinning, leaving one cluster/stalk in buckshot berry season, M4 - thinning, leaving one cluster/ stalk in verasion season) over leaf area, canopy structure, grape maturation and yield.
The thinning consisted on a qualitative cluster removal (two intensities) in two different seasons (buckshot berry and verasion).
The essay took place at “Herdade do Rocim”, sub region of Vidigueira in the wine region of Alentejo, in 2011, over the “Aragonês” and the “Alicante Bouschet” varieties.
When compared with the witness, the modalities of both varieties in which the thinning was made, presented differences in the yield (number of clusters, average production per plant, total production per hectare) although the M3 and M4 of “Aragonês” only diverged with M0 in the number of clusters. Despite of being less productive, the thinned modalities had a superior probable alcoholic content (PAC).
The modalities M3 and M4 presented a better balance between yield and PAC.
8
Mawdsley, Paul F. W. "The Effects of Cluster Thinning on Vine Performance, Fruit, and Wine Composition of Pinot Noir (Clone 115) in the Edna Valley of California." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2090.
Full textAbstract:
A three-year study was conducted at a commercial vineyard site in California’s Edna Valley AVA to evaluate the physiological and agronomical effects of the timing of cluster thinning on Pinot noir (clone 115) grapevines. Vines were thinned to one cluster per shoot at three selected time-points during the growing season (bloom, bloom + 4 weeks, bloom + 8 weeks), and fruit from each treatment was harvested and made into wine. Across all growing seasons, yield decreased 43% in thinned vines relative to un-thinned control vines. No effect of cluster thinning or interaction with growing season was found in vine shoot diameter, internode length, fruit zone light level, or cluster weight. Growing season significantly affected more fruit and wine parameters than did cluster thinning treatment, with interactions between treatment and growing season found in fruit Brix, titratable acidity, and anthocyanins, as well as wine anthocyanins and wine b* (yellow component). For example, bloom + 8 and bloom + 12 thinning treatments advanced Brix in 2017 but had no effect in 2018. Cluster thinning treatments increased berry anthocyanins by 43% in 2017 and by 103% in 2018 relative to the control. Similarly, cluster thinning increased berry total phenolics by 87% in 2017 and by 140% in 2018 relative to the control, with no significant differences found between the different thinning treatments. However, the levels of anthocyanins and total phenolics were generally not affected by cluster thinning treatment in the resulting wines. The fact that different cluster thinning treatments resulted in nil or minor effects on fruit and wine suggests that the vines tested were at or below a balanced crop load prior to the application of cluster thinning. Edna Valley AVA could likely support higher crop loads than 3.2 on the Ravaz index without negatively impacting fruit or wine composition and reducing crop load below that level is unlikely to increase fruit or wine quality.
9
Yoder, Carleton C. "Effect of vineyard management of Cabernet Sauvignon (Vitis vinifera L.) grape glycosides." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08222008-063601/.
Full text
10
Moreira, Manuel Adão Marques Pacheco Botelho. "Densidade do coberto e monda na casta Alfrocheiro na Região do Dão." Master's thesis, ISA/UTL, 2007. http://hdl.handle.net/10400.5/5088.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia<br>Throughout two years (2005 and 2006), have been studied the effects of three canopy
management techniques (reduction of shoot density, basal leaf removal and qualitative cluster
thinning), on the behaviour of the vine variety ‘Alfrocheiro’.
The trial, installed in Dão region, in a private vineyard (Dão Sul - Soc. Vitivinícola, S.A.),
had three shoot densities (test, 18 and 12 shoots/m of canopy), two different treatments of
basal leaf removal (test and basal leaf removal at veraison). Two treatments of qualitative
cluster thinning have also been evaluated (test and qualitative cluster thinning at veraison, of
the more delayed and with less quality clusters - “monda qualitative”).
The shoots suppression and basal leaf removal decreased the number of leaf layers, the
percentage of interior clusters and increased the penetration of the PAR in the fruit zone,
improving the clusters microclimate. The reduction of shoot density, as well as cluster
thinning, reduced the yield in both years. The basal leaf removal didn’t have any influence on
this parameter.
The factor “year” assumed a preponderant importance on grapes composition. Relatively to
the three studied canopy management techniques, they didn’t have a significant role in the
alteration of grapes characteristics. In what concerns to pruning, the most important result was
the reduction of the time of pruning in the lower densities.
11
Kaps, Martin L. "The influence of leaf, cluster, and berry thinning, and leaf position and shading on yield, juice composition and vine vigor of hybrid grapes /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487260531956664.
Full text
12
Alonso, Joana Maria Castelo Branco e. Costa. "Monda de cachos: efeito da época e intensidade na cv. Syrah." Master's thesis, 2009. http://hdl.handle.net/10400.5/1930.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia<br>Neste trabalho estudou-se o efeito da época e da intensidade de monda no rendimento e
qualidade da casta Syrah.
No ciclo vegetativo de 2008/2009 foi instalado um ensaio na Quinta do Monte D’Oiro,
em Alenquer. Esse ensaio repetiu-se em dois talhões (talhão 1 e 8).
Compararam-se duas épocas de monda - um mês após a floração (ou ao Bago de
Chumbo) e ao Pintor - e duas intensidades de monda : de 30% e 60% - associando ainda uma
testemunha sem monda.
Na produção e rendimento verificou-se uma diminuição não igual à intensidade de
monda. A realização de monda a 30% e 60% correspondeu, respectivamente, a reduções médias
no rendimento de 15,6% e 31,4%.
Os resultados obtidos mostraram que alguns compostos se encontram em concentrações
diferentes nas modalidades mondadas e não mondadas, contudo as diferenças não são
estatisticamente significativas.
Assim, quanto ao Grau Brix, ao teor de antocianinas, às proantocianidinas, % de galatos
e de epigalhocatequina não se verificou efeito significativo, quer da época de monda, quer da
intensidade de monda.
Alguns parâmetros contudo variaram reagindo à monda: ocorreu um aumento da acidez
total e dos fenóis na monda ao Pintor; os aromas aumentaram quando a monda se realizou a
60% e ao Pintor.------------------------------This work intended to study the effect of cluster thinning in cv. Syrah and its influence
on yield and analytical quality.
In this trial non thinned control was compared with two intensities of thinning (M30,
30% thinned and M60, 60%), and two thinning seasons: MBC – berries pea-sized and MPripening).
Thinning gave origin to a yield reduction, though not proportional to thinning intensity;
M30 reduction was 15,65% and M60’s reduction was 31,4%.
Analytical data -Brix, anthocyanins, proanthocyanidins - showed in general no
differences between control and thinned samples. Total acidity tended to increase as pH
diminished at ripening thinning. Phenols increased when comparing MP with control. Aromas
were improved when thinning was made at MP and M60.
13
Silva, Maria Jacinta Nunes da Costa Gomes Sobral. "Controlo do rendimento na casta Aragonez." Master's thesis, 2009. http://hdl.handle.net/10400.5/2455.
Full textAbstract:
Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Universidade do Porto<br>The purpose of the present work was to study the effects of the cluster thinning at veraison in
the yield, grape composition and wine quality of the Aragonez variety in a trial located at Quinta
do Pinto vineyard, Merceana. The experimental design consisted in randomizes blocks, with four
blocks and two treatments, named M and T, which correspond, respectively, to a 50% and 0%
intensity of the cluster thinning. Vine and fruit measures were performed during ripening and at
harvest. Under the seasonal conditions experienced the cluster thinning, lead to a 40% decrease
in the yield as well as higher total soluble solids. The other grapes attributes did not show any
significant differences at harvest in the remaining tested parameters. The preliminary wine
sensory analysis indicates that there weren´t detected sensory differences attributes in wine made
from cluster thinning treatments. The cluster thinning, by accelerating the ripening, allowed
anticipating the harvest, reducing the grapes from the early rains, with benefic consequences for
the grape quality as it doesn’t allow the dilution of its components and avoid the development of
the Botryis cinerea Pers.
14
SKRAB, DOMEN. "Metabolic modifications occurring during maturation in Ribolla Gialla grapes, and implication of vineyard site, cluster thinning, and harvest time on the composition and the sensory evaluation of sparkling wines." Doctoral thesis, 2021. http://hdl.handle.net/10449/69667.
Full textAbstract:
Ribolla Gialla (Vitis vinifera L.) is an indigenous white grape variety cultivated in
northeastern Italy, in Slovenia and on the Ionian Islands in Greece, where it is known as
Rebula and Robola, respectively, and can be considered as one of the most promising for
producing high-quality monovarietal sparkling wines. However, due to its neutral aromatic
potential, the manipulation of wine quality thus mainly depends on the application of
viticultural or oenological practices. For instance, cluster thinning is a commonly adopted
viticultural technique for selective removal of excessive clusters and allows calibrated vine
productivity with increased accumulation of metabolites in the fruit. Modulating of wine
grapes yield will therefore activate the intrinsic changes in basic berry composition
(including soluble solids, organic acids, pH phenolics and anthocyanins), resulting from
thinning treatment, while also changing the rate of grape ripening. Consequently, monitoring
the ripening of the grapes is important mainly to determine the ideal harvest time. As this
study shows, different harvest times have a significant impact on chemical composition of
wines, which can lead to different sensory characteristics. The objective of this research
work was therefore to produce a comprehensive study of discussed viticultural measures in
the production of monovarietal Ribolla Gialla sparkling wine from two different locations.
The position of vineyard site should not be neglected, as it is an integral part of the terroir,
that can be defined as an ecosystem, in a given place, including factors like climatic
conditions, cultivar and rootstock, geography and topography, as well as soil characteristics
like mineral nutrition and water supply. For this purpose, the multi-targeted approach was
adopted, using different analytical techniques (GC-MS, UPLC-MS, and FTIR) to investigate
the aromatic characteristics of the sparkling wines obtained, including their volatile organic
composition, lipid compounds, and the metabolites of aromatic amino acids, which play a
key role in the organoleptic and sensory properties of wine. The findings of this study could
provide a sort of guideline, intended for winegrowers and professional experts, designed to
facilitate the decision about the level of production, or to help out determine the optimal
harvest time, by taking into account changing climatic conditions.
15
Rodrigues, Carlos Alberto da Costa. "Estratégias de gestão do coberto vegetal e da produção na casta Touriga-Nacional na Região do Dão." Master's thesis, 2009. http://hdl.handle.net/10400.5/1899.
Full text