• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 119
  • 92
  • 57
  • 29
  • 24
  • 24
  • 19
  • 10
  • 4
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 419
  • 128
  • 106
  • 76
  • 73
  • 70
  • 70
  • 68
  • 41
  • 35
  • 33
  • 33
  • 27
  • 27
  • 26
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Efeito dos fungicidas mancozeb, captan e dithianon sobre Saccharomyces cerevisiae

Scariot, Fernando Joel 13 December 2016 (has links)
Os fungicidas são normalmente utilizados para o controle de doenças causadas por fungos fitopatogênicos em diversas culturas, incluindo frutas. Estes compostos, especialmente os descritos com atividade em múltiplos alvos, podem afetar organismos não alvos como leveduras, levando elas à morte por diferentes vias. O objetivo deste trabalho foi determinar o mecanismo de ação e de morte de três diferentes fungicidas utilizados na viticultura (mancozeb, captan e dithianon) sobre Saccharomyces cerevisiae. Os resultados mostraram que leveduras expostas ao mancozeb (100 µM, 6 h) levam a uma drástica redução da viabilidade, mas sem modificações na integridade da membrana celular. As células tratadas com mancozeb apresentaram marcadores apoptóticos como aumento na concentração intracelular de espécies reativas de oxigênio (ROS), hiperpolarização da membrana mitocondrial e externalização de fosfatidilserina, indicando que a morte celular de S. cerevisiae ocasionada por mancozeb é apoptótica e conforme observado pelo comportamento de linhagens mutantes, segue a via metacaspase dependente. Aproximadamente 80% das leveduras tratadas com captan (20 µM, 6 h) apresentaram disfunções na membrana citoplasmática, e a drástica redução na concentração de grupos tiólicos proteicos e não proteicos. Além disso, as células que mantiveram sua integridade de membrana após a exposição ao captan, exibiram externalização de fosfatidilserina e acumulação de ROS. Mutantes com deleção em YCA1 apresentaram resistência parcial ao captan, indicando a ativação da cascata apoptótica metacaspase dependente. Em fermentações vínicas o captan (2,5 µM) atrasa o início da fermentação de maneira dose dependente, devido à drástica redução na viabilidade celular. Porém, em dosagens subletais, as células remanescentes se adaptam ao fungicida e completam a fermentação sem alterações evidentes nas características físico-químicas do produto final. Da mesma forma, leveduras tratadas com dithianon (2 µM; 3 h) mostraram aumento no número de células com permeabilização da membrana citoplasmática, aumento de ROS e redução na quantidade de tióis, mas sem sinais de apoptose. De forma geral, os resultados indicam que o mancozeb induz apoptose em S. cerevisiae via metacaspase dependente, enquanto o captan leva a morte por necrose e apoptose e o dithianon mata as células por necrose. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / Fungicides are currently used to control fungal phytopathogenic diseases in many crops, including fruits. These compounds, especially those described as multisite activity fungicides, can affect non-target organisms like yeasts leading to their cell death by different pathways. The objective of this work was determining the mechanism of action and death of three fungicides used in viticulture (captan, dithianon and mancozeb) on Saccharomyces cerevisiae. The results showed that yeast exposition to the mancozeb (100 µM, 6 h) lead to a drastic reduction of cell viability, but no modification of cell membrane integrity. Mancozeb treated cells shown apoptotic markers as increase of intracellular reactive oxygen species (ROS), mitochondrial membrane hyperpolarization, and phosphatidylserine externalization, indicating that mancozeb induced cell death in S. cerevisiae is apoptotic and as shown by mutants strains, follow metacaspase-dependent pathway. Almost 80% of captan treated yeasts (20 µM, 6 h) showed citoplasmatic membrane dysfunction, and a drastic reduction on both non-proteic and proteic thiol concentrations. Moreover, the cells that retain their membrane integrity after exposure to the captan exhibited phosphatidylserine externalization and ROS accumulation, indicating apoptosis. YCA1 deletion mutant exhibited partial resistance to captan, suggesting a metacaspase dependent apoptotic cascade. In wine fermentations captan (2,5 µM) delays the beginning of alcoholic fermentations in a dose dependent manner, associated with a drastic reduction on yeast viability. However, in sub-lethal dosages, the reminiscent viable cells adapted to the fungicide, grow and complete fermentation with non-evident modifications on the physicochemical characteristics of the final product. Similarly, yeast cells treated with dithianon (2 µM; 3 h) showed cell membrane permeabilization, ROS increase, and decrease of cellular thiol compounds, but no signs of apoptosis. In general, the results indicated that mancozeb induces metacaspase dependent apoptotic cell death in S. cerevisiae, where captan leads to a dual necrotic and apoptotic cell death, and dithianon kills cells by necrosis.
72

Understanding Brand Coolness: An Investigation into Brand Coolness and its Impact on Wine Consumers

Nutta, Marco 01 January 2022 (has links) (PDF)
The concept of brands and the process of branding have been in use for centuries (Nancarrow & Nancarrow, 2007). Branding has enabled producers to differentiate their products more easily from one another. In addition to product differentiation, brands also communicate a firm's values through a variety of names, slogans, symbols, and designs. Through a process of communication, brands can facilitate a relationship-building process that can mimic human-to-human interactions. In the current market, it is an ongoing challenge for firms to stay current with consumer trends. Keeping up with what is considered cool can often determine a firm's success. Traditionally coolness has been considered a human attribute. However, in recent years, it has also been associated with inanimate objects and brands (Belk, 2006). Firms that strive to be perceived as cool have been shown to be more noticeable and are viewed more positively. Although coolness is ubiquitous in marketing and branding practices, it is still unclear how it is positioned amongst other branding constructs. Due to its similarities, scholars have often placed brand coolness alongside brand personality, yet there is a need to confirm its relationship with brand personality (Warren et al., 2019). In addition, considering brand personality's important role in understanding brand identity (Kapferer, 2012), the relationship between brand coolness and brand identity needs to be explored, as brand identity is known to influence purchase intentions (You & Hon, 2021). Lastly, this dissertation aims to examine the practical applications of brand coolness and its impact on wine consumer attitudes and behaviors. To address these issues, this dissertation conducted three studies. The first and second studies applied survey research design and generated a self-administered online questionnaire that was hosted on Qualtrics.com and MTurk. Anderson & Gerbing's two-step approach to SEM was applied and the data were analyzed to investigate brand coolness, brand personality, brand identity, and purchase intentions. The third study applied a between-subjects quasi-experimental design and examined the impacts of wine brand characteristics on perceived brand coolness, purchase intentions, and willingness to pay more. The results suggest that brand coolness is a separate construct from brand identity, that brand coolness plays an important role in the understanding of brand identity and its relationship with purchase intentions, and that brand characteristics, such as celebrity association, can have a positive impact on perceptions of brand coolness, intentions to purchase, and consumers' willingness to pay more for cool products. This dissertation provides important theoretical and managerial implications by establishing and confirming the relationship between brand coolness and brand personality, proposing brand coolness as a central component of brand identity, and providing practical applications for wine brands that utilize brand coolness to influence consumer attitudes and behavior.
73

Touriga Naçional x environment interaction in the Little Karoo region of South Africa

Nel, Margaux 12 1900 (has links)
MScAgric / ENGLISH ABSTRACT: The Little Karoo region of South Africa stretches from Montagu in the west, through Barrydale on the Langeberg Mountain, towards Ladismith, Calitzdorp, Oudtshoorn and De Rust in the east, with the Swartberg mountain range in the north. The Wine of Origin district of Calitzdorp is a small, demarcated area around Calitzdorp in the Little Karoo, surrounded by the Rooiberg, Swartberg and Kleinberg mountains. With a mean February temperature (MFT) of 23.7ºC and a low annual rainfall of 233 mm, the district of Calitzdorp has a similar climate to that of the Douro Demarcated Region (DDR). The MFT is comparable to the DDR mean July temperature, and it seems that the Douro Superior sub-region to the east of the DDR has a mean July temperature of higher than 25°C. In the Cima Corgo sub-region (in the centre of the DDR), and the Baixo Cargo sub-region, the mean July temperatures are ±25°C and ±22°C respectively. Annual rainfall in the DDR is much higher, with Baixo Cargo recording 1 018 mm, Cima Corgo recording 658 mm and Douro Superior in the east recording only 437 mm. Touriga Naçional is one of the highest quality Portuguese red grape varieties. It produces high-quality port-style wine as well as table wines. Excellent quality Touriga Naçional wines have a dark black/purple colour, good extract, high, elegant tannin content and intense aromas, with typical plum, raisin, wild fruit, mulberry, “fynbos” and cherry aromas. The most suitable terroir for Touriga Naçional in the DDR has been found to be on sites that restrain the natural vigour of the grapevine. Soils with moderate to low water-holding capacity, in association with low rainfall, result in water deficits during the growing season and are considered optimal to restrict growth vigour. A steep, northern middle slope is ideal in the southern hemisphere for high temperatures and sunlight interception. Warm temperatures (25 to 30 °C) during the day and cooler temperatures during the night are optimal for photosynthesis and colour development. In order to study factors affecting the quality of Touriga Naçional in Calitzdorp, two Vitis vinifera L. cv. Touriga Naçional commercial vineyards in the Calitzdorp district were selected. Each vineyard was divided into two separate management blocks based on their empirically determined quality of production. Two crop-reduction treatments, the standard 50% crop reduction (which was considered to be the control) and a further less drastic treatment of 25% crop reduction, were applied. Significant differences were found in viticultural performance between the two adjacent Touriga Naçional management blocks in each vineyard, especially with respect to vigour. The upper management blocks, which provided grapes for reserve-quality port-style wines, experienced a higher water deficit due to the moderate soil water-holding capacity and higher temperatures in comparison to the lower sites. The higher water deficits had a restraining effect on the Touriga Naçional vines, and therefore the upper sites had lower vigour, which contributed to better quality of both the wine and port-style wine, and this could be recognised sensorially. However, it was not reflected in the chemical analytical results. Crop load also appeared to have an effect on the Touriga Naçional grapevines, but this appeared to be dependent on the management block. The 50% crop reduction had a significant positive effect on the sensory analyses, but did not significantly affect the chemical analyses. Calitzdorp terroir has a similar effect on Touriga Naçional compared to the DDR terroir, and that is why Calitzdorp can produce good table and port-style wines from Touriga Naçional. / AFRIKAANSE OPSOMMING: Die Klein Karoo-streek in Suid Afrika strek vanaf Montagu in die weste, deur Barrydale teen die Langeberg, na Ladismith, Calitzdorp, Oudtshoorn en De Rust in die ooste, met die Swartberg in die noorde. Die distrik van Calitzdorp is ‘n klein area rondom Calitzdorp, in die Klein Karoo, wat deur die Rooiberg, Swartberg en Kleinberg omring is. Calitzdorp het ‘n gemiddelde Februarie-temperatuur (GFT) van 23.7°C en ‘n lae jaarlikse reënval van 223 mm, wat soortgelyk is aan die klimaat van die Douro Vallei in Portugal. Die Douro Vallei se gemiddelde Julie-temperatuur (GJT) in vergelyking met die GFT van Calitzdorp is hoër, met temperature van meer as 25°C in die substreek Douro Superior. Vir die substreke Cima Cargo en Baixo Cargo is die GJT ±25°C en ±22°C onderskeidelik. Die jaarlikse reënval is ook hoër by Baixo Cargo, met 1 018 mm, Cima Cargo met 658 mm en Douro Superior met slegs 437 mm. Touriga Naçional is een van die beste Portugese rooi kultivars wat hoëkwaliteit tafel- en portwyne produseer. ‘n Tipiese hoëkwaliteit Touriga Naçional-wyn het ‘n swartpers kleur, hoë ekstrak, hoë elegante tanniene en intense aromatiese geure wat tipiese pruim, rosyne, wilde vrugte, moerbei, fynbos en kersie aromas insluit. Die geskikste terroir vir Touriga Naçional is op swak gronde wat die natuurlike groeikrag van die wingerdstok strem. Gronde met matige tot lae grondwaterhouvermoë tesame met lae reënval veroorsaak ‘n waterstremming in die wingerdstok gedurende die groeiseisoen en word as optimaal beskou omdat dit beheersde groei veroorsaak. In die suidelike halfrond word relatief steil, noordelike middelhange as ideaal beskou vir hoë temperature en maksimale sonligonderskepping. Gepaardgaande hiermee is die interne dreinasie verantwoordelik vir vinniger uitdroging van die grond. Hoë temperature (25 tot 30°C) gedurende die dag en koue nagte is optimaal vir fotosintese en kleurontwikkeling. Twee Vitis vinifera L. cv. Touriga Naçional kommersiële wingerde in die Calitzdorp-distrik is geselekteer en in twee afsonderlike bewerkingsblokke verdeel, gebaseer op kwaliteitsverskille. In elke blok was die verdeling van so ‘n aard dat daar ‘n hoërliggende helfte en ‘n laerliggende helfte was. Twee trosverminderingsbehandelings, nl. 50% (kontrole) en 25%, gebaseer op trosgetalle, is toegepas. By elkeen van die wingerde was daar betekenisvolle groeiverskille tussen die twee aangrensende helftes. Die boonste helftes (of gedeeltes) het minder gegroei a.g.v. ‘n hoër waterstremming sowel as hoër temperatuur as die laer helftes. Dit het geblyk om ‘n positiewe invloed op die kwaliteit van beide die tafel- en portwyne uit te oefen. Troslading het ook ‘n effek op die Touriga Naçional-wingerde gehad, maar dit blyk of dit blok-afhanklik is. Die 50% trosverminderingsbehandeling het ‘n beduidende positiewe verskil in die sensoriese analises gemaak, maar nie ‘n beduidende verskil in die chemiese analises van die wyne nie. Calitzdorp se terroir het ‘n soortgelyke effek op Touriga Naçional as dié van die DDR terroir en daarom kan Calitzdorp soortgelyke goeie tafel- en portwyne van Touriga Naçional produseer.
74

Influence of soil parameters and canopy structure on root growth and distribution

Serra-Stepke, Ignacio M. 03 1900 (has links)
Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Because of long-term climate changes, apparently associated with higher temperatures and fewer rainfall events, factors such as water-use efficiency and site selection for new cultivars are a matter of increasing importance for viticulture. Within this context, the root system is expected to play a key role. Its relevance to grapevine functioning is due to the numerous functions in which it is involved. In the light of this, the development of the root system is highly relevant to the viticulturist because of the fact that grapevine growth and functioning are dependent on the development of the root system. Differences can, therefore, be expected in terms of berry ripening on single grapevines of the same scion for situations with differing development of root systems, despite being grafted on the same rootstock. Root growth is influenced by several factors, among the ecological aspects. Soil parameters have a predominant influence on root growth and distribution but also annual root production can be altered by canopy manipulation. Due to the importance of root growth to the aboveground development of the vine, it is critical to gain understanding of the relationship between soil factors and root growth and distribution, and the central role that the subterranean environment plays in the concept of terroir. This study aimed to investigate the effect of selected soil physical and chemical parameters on root growth and distribution and to investigate whether having very different canopies influences root growth. In order to achieve these goals, two experiments were conducted; the first was performed in two commercial Sauvignon blanc vineyards each grafted onto Richter 110, non-irrigated, with two treatments: undisturbed lateral growth and complete lateral removal. The second study included the analysis of eight commercial Sauvignon blanc vineyards grafted onto Richter 99 and Richter 110 located in the Stellenbosch Wine of Origin District. Measurements of physical and chemical soil parameters, root growth and distribution, canopy growth and functioning, vine water status and berry composition were performed. The edaphic factors appeared to be one of the most important parameters that affected root development by changing soil water availability and possibly causing physical or chemical limitations on root growth. From the results of this study, it is clear that severe water stress and a pH (KCl) lower than 4.5 play a key role in the limitation of root growth. Due to the fact that most of the soils from the Stellenbosch Wine of Origin District, especially the subsoils, are acidic, this is a factor to consider before planting. On the other hand, the combination of favourable edaphic conditions, such as a subsoil pH of higher than 5.0, light- to mediumtextured subsoil and moderate water stress, allow increased growth of thin roots. However, the effect of canopy management on root growth cannot be discounted due to its importance in the variation of carbohydrate demand by competing sinks. This study showed that lateral removal done from when the berries are at pea size results in an increase in the number of thin roots (0.5-2.0 mm). The secondary leaf area represents at least the same leaf area as the primary leaf area in all the vineyards evaluated, which reveals the relative importance of the laterals in the total leaf area of the vine and the potential importance in terms of microclimate and leaf area available for photosynthesis. Studies of root growth should take the vineyard canopy architecture into account. / AFRIKAANSE OPSOMMING: As gevolg van langtermyn klimaatsveranderinge wat toegeskryf kan word aan die voorkoms van hoër temperature en laer reënval, is faktore soos effektiwiteit van waterverbruik en liggingseleksie vir nuwe kultivars van kardinale belang vir wingerdkunde. Binne hierdie konteks, speel die wortelsisteem ‘n belangrike rol. Die belangrikheid hiervan vir wingerdfunksionering kan toegeskryf word aan die talle funksies waarby dit betrokke is. Die ontwikkeling van die wortelsisteem is dus hoogs relevant vir die wingerdkundige, omdat wingerdgroei en funksionering afhanklik is van die ontwikkeling van die wortelsisteem. Verskille kan daarom dus verwag word in terme van korrelrypwording op ‘n enkele wingerdstok van dieselfde onderstok vir gevalle met verskillende ontwikkeling van die wortelsisteem, ten spyte daarvan dat dit op dieselfde onderstok geënt is. Wortelgroei word, onder ekologiese aspekte, deur verskillende faktore beïnvloed. Grondfaktore het meerendeels ‘n predominante invloed op wortelgroei en -verspreiding, terwyl jaarlikse wortelproduksie deur lowermanipulasie beïnvloed kan word. Weens die belangrikheid van wortelgroei vir die bogrondse ontwikkeling van die wingerd, is dit krities om kennis op te doen oor die verhouding tussen grondfaktore en wortelgroei en –verspreiding, asook die sentrale rol wat die subterreinomgewing op die terroir-konsep speel. Die studie was daarop gemik om die invloed van geselekteerde fisiese en chemiese parameters van grond op wortelgroei en -verspreiding vas te stel, en ook te ondersoek of verskillende lowers wortelgroei sal beïnvloed. Om laasgenoemde doelwitte te bereik, is twee eksperimente uitgevoer. Die eerste is uitgevoer in ‘n kommersïele Sauvignon blanc-wingerd wat geënt is op Richter 110, sonder besproeïng en met twee behandelings, naamlik onversteurde sêkondere lootgroei en volledige sêkondere lootverwydering. Die tweede studie het die analise van agt kommersïele Sauvignon blancwingerde geënt op Richter 99 en Richter 110 in die Stellenbosch Wyn van Oorsprong Distrik. Metings van fisiese en chemiese grondfaktore, wortelgroei en -verspreiding, lowergroei en -funksionering, plantwaterstatus en korrelsamestelling is uitgevoer. Dit blyk dat edafiese faktore een van die belangrikste parameters is wat wortelontwikkeling beïnvloed deur beskikbaarheid van grondwater te verander, en wat moontlik fisiese en chemiese beperkings op wortelgroei kan veroorsaak. Uit die resultate van die studie is dit duidelik dat intense waterspanning en ‘n pH (KCl) laer as 4.5 ‘n belangrike rol in die beperking van wortelgroei speel. Aangesien die meeste van die grondsoorte in die Stellenbosch Wyn van Oorsprong Distrik, veral al die subgronde, suur is, is dit ‘n faktor wat in oorweging geneem moet word voor aanplantings. Die kombinasie van gunstige edafiese toestande, soos ‘n subgrond met ‘n pH hoër as 5.0, ‘n lig tot medium tekstuur en matige waterspanning, sal dus aanleiding gee tot ‘n toename in die groei van dun wortels. Die effek van lowerbestuur op wortelgroei kan egter nie buite rekening gelaat word nie weens die belangrikheid daarvan in die variasie van koolhidraataanvraag deur kompeterende vraagpunte. Hierdie studie toon dat, indien sêkondere lootverwydering tydens ertjiekorrelgrootte toegepas is, dit aanleiding gee tot ‘n toename in die dun wortels (0.5 tot 2.0 mm). Die sêkondere blaaroppervlakte verteenwoordig minstens dieselfde blaaroppervlakte as die primêre blaaroppervlakte in al die wingerde wat ondersoek is, wat dui op die belangrikheid van sêkondere lote in die totale blaaroppervlakte van die wingerd en die potensiële belangrikheid daarvan in terme van mikroklimaat en blaaroppervlakte wat vir fotosintese beskikbaar is. Studies van wortelgroei moet lowerargitektuur in ag neem.
75

Spatial characterisation of natural terroir units for viticulture in the Bottelaryberg-Simonsberg-Helderberg winegrowing area

Carey, Victoria Anne 04 1900 (has links)
Thesis (MScAgric) -- University of Stellenbosch, 2001. / ENGLISH ABSTRACT: There is an increasing demand by the consumer for knowledge and understanding of the origin of each wine produced. This origin is directly linked to the interaction between the environment and grapevine, and therefore to the terroir. A terroir can be defined as a complex of natural factors being expressed through the final product and must therefore be studied in two steps, namely, the identification of relatively homogenous natural terroir units followed by their ecophysiological characterisation. The aim of this study was to characterise the Bottelaryberg-Simonsberg-Helderberg wine growing area according to existing digital information and to identify natural terroir units. The study area is situated to the southwest of Stellenbosch and covers an area of approximately 25 000 ha. Topography is a static feature of the landscape and affects the sunlight interception by a slope, exposure of a site to winds and drainage of soil water and air. It forms an important component of the terroir concept and has a strong interaction with the environmental components of climate and soil. The study area is bordered by mountains and bisected by a river valley resulting in a large variation in aspect and altitude affecting both spatial and temporal temperature variability. There is no doubt as to the important effect of climate on wine character and quality. A number of indices can be used to describe the regional climate. The study area has a Mediterranean climate with notable spatial variation of all climatic parameters due to its complex topography and proximity to the ocean. The effect of geology on wme character is less clear but appears to act through its contribution to the physical properties of the soil. In the Bottelaryberg-Simonsberg- Helderberg study area the geology is complex due to the high degree of tectonic movement and mixing of parent material. In situ weathering of rocks is seldom the only source of soil formation. Soil has a number of contributing factors affecting wine character and quality, inter alia, soil colour, temperature, chemical composition, depth and texture (affecting the water supplying properties of the soil). It is the last two that appear to have the most significant effect. Soil depth affects the buffer capacity of the soil to temper climatic extremes and the water supply has a well-recorded effect on vine growth and functioning. There is a high degree of soil variation in the Bottelaryberg-Simonsberg-Helderberg study area that is difficult to represent in soil associations. A pattern of soil distribution, however, can be noticed in relation to landscape variation. Terrain morphological units, altitude and aspect were used as pnmary keys for the identification of natural terroir units. Broad soil categories and geological information were included at a secondary level. This resulted in 195 units. These natural terroir units will form the basis for future ecophysiological characterisation in order to determine possible future cultivar distribution as well as the terroir effect on wine character. / AFRIKAANSE OPSOMMING: Daar is toenemende aanvraag vanaf die verbruiker vir kennis en begrip van die oorsprong van elke wyn wat geproduseer word. Die oorsprong is direk aan die interaksie tussen die omgewing en wingerd gekoppel, en daarom ook die terroir. Terroir kan omskryf word as die kompleks van natuurlike faktore wat in die finale produk uitdrukking vind en studies daarvan moet dus in twee stappe plaasvind, d.i. die identifisering van relatiewe homogene natuurlike terroir eenhede gevolg deur die ekofisiologiese karakterisering daarvan. Die doel van die studie was om die Bottelaryberg-Simonsberg-Helderberg wynproduserende gebied te karakteriseer, met behulp van bestaande versyferde data en om natuurlike terroir eenhede te identifiseer. Topografie is 'n vaste landskapskenmerk en beïnvloed sonligonderskepping deur hellings, blootstelling van 'n ligging aan wind en die dreinerin~ van grondwater en beweging van koue lug. Dit is 'n belangrike deel van die terroir konsep en het sterk interaksie met omgewingsfaktore van grond en klimaat. Die studiegebied word begrens deur berge en is deursny deur 'n riviervallei, met groot variasie in helling en aspek. Beide hiervan beïnvloed die ruimtelike- en daaglik-variasies in daaglikse maksimum temperatuur. Die belangrike effek van klimaat op wynkarakter en kwaliteit is duidelik soos weerspieël deur die beskikbaarheid van 'n aantal makroklimaatsindekse. Alle klimaatsparameters word deur topografie beïnvloed. Temperatuur en relatiewe humiditeit word ook deur afstand vanaf die see beïnvloed. Die studie area het 'n Meditereense klimaat, met merkwaardige ruimtelike variasie van alle klimaatsparameters. Die effek van geologie op wynkarakter is minder duidelik, maar het waarskynlik 'n effek op die fisiese eienskappe van 'n grond. Die geologie in die Bottelaryberg-Simonsberg- Helderberg studiegebied is kompleks, as gevolg van die hoë graad van tektoniese beweging en vermenging van moedermateriaal. In situ vorming van gronde uit gesteentes vind selde plaas: Grond het 'n groot aantal bydraende faktore, wat wynkarakter en -kwaliteit kon beïnvloed, onder andere, grondkleur, -temperatuur, -chemiese samestelling, -diepte en -tekstuur (wat die waterleweringsvermoë van die grond bepaal). Dit is veral laasgenoemde twee faktore wat blykbaar die mees opvallendste effek openbaar. Gronddiepte bepaal die buffer kapasiteit van die grond om klimaatsuiterstes te kan weerstaan en die waterleweringsvermoë het 'n alombekende effek op wingerdgroei en funksionering. Daar is 'n hoë graad van grondvariasie in die Bottelaryberg-Simonsberg-Helderberg studiegebied wat moeilik is om met grondassosiasies weer te gee. Daar is wel 'n patroon van grond distribusie wat verband hou met landskapvariasie. Terrein morfologiese eenhede, hoogte en aspek is gebruik as primêre sleutels vir die indentifisering van natuurlike terroir eenhede. Globale grondkategorieë en geologiese inligting is op 'n sekondêre vlak gebruik. Dit het 195 eenhede tot gevolg. Die natuurlike terroir eenhede sal die basis vorm vir toekomstige ekofisiologiese karakterisering, om die terroir effek op wynkarakter te kan bepaal.
76

Wingerdoorentingstudies

Orffer, C. J. (Christian Johannes) 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 1954. / No Abstract Available
77

Effects of vine architecture on water use, microclimate, fruit composition, and yield of Vitis vinifera L. 'Petite Sirah' grapevines.

Morsi, Taher Hussein. January 1991 (has links)
Effects of trellising on water use, absorption of photosynthetically active radiation (PAR, 400 to 700 nm wavelength) by foliage and potentially by fruit, fruit composition, and yield were studied in 1988 under semi-arid conditions on field-grown Vitis vinifera L. 'Petite Sirah' grapevines in a mature vineyard. The positioning of shoots on trellises resulted in canopies that were (1) positioned vertically (vertical canopy), (2) positioned in a "V" pattern with sides inclined 60° from horizontal (inclined canopy), and (3) inclined toward the vineyard floor (standard canopy). Seasonal water use values determined from neutron scattering data were 393 ± 61, 554 ± 73, and 455 ± 57 mm for the standard, vertical and inclined canopies, respectively. On average, about 50% of seasonal water consumption occurred between fruit set and filling stages for each type of canopy. Average crop factors (ratio of actual to reference crop evapotranspiration) of 0.383, 0.540 and 0.444 were for the period bud burst to harvest for standard, vertical and inclined canopy systems, respectively. The diurnal water use patterns of the three trellising canopies were very similar when measured by either the heat pulse technique or by porometer. The average daily heat pulse velocity (HPV) for selected vertical, inclined and standard canopies for 6 days were 8.77, 7.58 and 6.85 cm h⁻¹, respectively. The HPV technique indicated that the average daily water use of the whole plant was 0.227, 0.192 and 0.137 kg/m² leaf area/d for standard, vertical and inclined canopies, respectively. The daily average transpiration rates as measured by the HPV technique were 32, 31, and 25% higher than the average transpiration rates estimated from porometer data for standard, vertical and inclined canopies, respectively. Stomatal conductances of the vertical and inclined canopies were 20 and 40%, respectively, below that of standard canopy. PAR absorption by foliage during mid-day was highest in the standard trellis, and lowest in the inclined trellis. PAR potentially available for absorption by fruits was lowest in the standard trellis, and highest in the inclined trellis. In both inclined and vertical canopies, the average sunfleck values were 26%, but was only 2% in the standard canopy. Analysis of fruit composition at harvest revealed that total dissolved solids (°Brix) was significantly higher in the inclined trellis than for the vertical trellis or the standard trellis. The inclined trellis resulted in the highest alcohol content of wine. Per vine yields did not differ significantly among the three trellis systems. Overall, the standard trellis was optimum because grapevines consumed less water and produced a shading which protected the fruit from direct solar radiation.
78

BUDBREAK AND FRUITFULNESS OF DESERT GRAPES (VITIS VINIFERA L.) (DEFOLIATION, PRUNING, HORMONES).

DUARTE, MIGUEL ANGEL. January 1983 (has links)
Dinitro-ortho-cresol (500, 1000, and 2000 ppm) and dormant oil (2.5, 5.0, and 10%) were applied to Thompson Seedless and Perlette grapevines alone and in combination to enhance budbreak and fruitfulness. Applications were made immediately after pruning. Use of these materials during the winter, immediately after pruning, had no effect on either fruitfulness or budbreak in Perlette or Thompson Seedless. Thompson Seedless cuttings collected in August were exposed to six temperatures (7, 13, 18, 24, 29 and 35 C) for five time periods (2, 4, 6, 8 and 12 weeks). After temperature treatment the cuttings were planted in the greenhouse at 24 (+OR-) 1 C. Cuttings exposed to 24, 29 and 35 C broke sooner than those exposed to 7, 13, 18 C at all time periods. The percentage of the bud openings of cuttings at 29 C for a period of 2 and 4 weeks was 95% and 100% respectively. The optimum temperature for budburst was 29 C. Gibberellic acid, Thiourea, dinitro-ortho-sec-butyl-phenol (DINOSEB), potassium nitrate and Endothal were used at two concentrations alone and in combination, to break rest of Thompson Seedless buds. Thiourea at 2% and DINOSEB at 1000 ppm alone were the only treatments which gave a higher percentage of bud opening after 20 forcing days at 25 (+OR-) 1 C temperature. Similar results were obtained from cuttings taken in both winter and summer. Three times after harvest, Perlette and Thompson Seedless were defoliated using the senesce enhancer Endothal. Defoliation times (4, 8, and 12 weeks) after harvest were used. In half of the treatments, regrowth was controlled with Endothal. Gibberellic acid (1000 ppm) Thiourea (2%) and DINOSEB (2000 ppm) were applied at the time of defoliation. The four- and twelve-week defoliation periods with new vine growth controlled for improving budbreak and fruitfulness were best. Growth regulators did not improve the defoliation treatments. The best treatments hastened budbreak by 10 days, more than doubled vine fruitfulness, and increased sugar content in berries resulting in a 10-day earlier harvest than in the control. Results were similar in both Thompson Seedless and Perlette. Thompson Seedless and Cardinal vines grown under Arizona desert conditions were defoliated 4 weeks after harvest with 2000 ppm Endothal. Two weeks later they were pruned and treated with 1000 ppm gibberellic acid, 2% Thiourea, and 1000 ppm DINOSEB. Cardinal and Thompson Seedless vines produced a second commercial crop in December of the same year. Thiourea (2%) and 1000 ppm DINOSEB did not have a significant effect; however, 1000 ppm Gibberellic acid reduced the number of clusters per vine.
79

Establishing a Commercial Vineyard in Arizona

Crider, F. J. 06 1900 (has links)
This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.
80

The basis of variation in the size and composition of grape berries

Gray, John D. January 2002 (has links) (PDF)
"Department of Horticulture, Viticulture and Oenology, Faculty of Agriculture and Natural Resource Sciences, The University of Adelaide, Waite Campus, Glen Osmond S.A." Bibliography: leaves 136-149 This investigated focussed on selected aspects of berry development and ripening that were subject to variation. Shiraz and Chardonnay were chosen as experimental varieties because these cultivars presented a large range of variability in the field. The extent of the variation within each of the recorded berry parameters was assessed using the coefficient of variation (CV), a unitless measure of sample variability relative to the sample mean, ideally suited to comparative studies.

Page generated in 0.0426 seconds