Studies showed that the ultraviolet irradiation and the cold in woven of plants present some effect on the metabolism of phenolics compounds. The polyphenols are a group of substances present in the wine responsible for causing a series of benefits to the man's health and they are also important in the quality of the wine. The present work was proposed with the objective of comparing wines coming from grapes in wine varieties Cabernet Sauvignon and Chardonnay exposed to cold, ultraviolet irradiation and a subsequent storage, verifying their effects in the quality of wine through physiochemical analyses, biochemistries and sensorial. In the physiochemical analyses of the variety Cabernet Sauvignon were found small differences in the values of total acidity, however for the phenolics compounds, it happened larger variations, with the following results: Cold-irradiated 9723.3 mg EAG, Irradiated 6631.7 mg EAG, Cold-control 2696.7 mg EAG, Control 2258.3 mg EAG and Pattern 1150.0 mg EAG. In the determination of the % of inhibition of the antioxidant activity there were also significant differences, reflecting the same previous order with the following values: Cold-irradiated 97. 17%, Irradiated 88.50%, Cold-control 61.3%, Control 55.24% and Pattern 41.50%. For the variety Chardonnay, the values of the analyses physiochemical just obtained small differences in the pH, in the total and volatile acidity. For the values of the phenolics compounds, a larger variation was observed, where the values were: Cold-irradiated 91.44 mg EAG, Irradiated 76.06 mg EAG, Cold-control 70.13 mg EAG, Pattern 8.99 mg EAG and Control 8.94 mg EAG. Was observed in the determination of the % of inhibition of the antioxidant activity, that showed significant differences reflecting the same order previous with the following values: Cold-irradiated 91.35%, Irradiated 75.94%, Cold-control 70.67%, Control 24.13% and Pattern 9.13%. In the sensorial analysis of the wines of the two cultivate, just the trained panel of judges knowledgeable in wines distinguished the alterations correctly in the wines for the triangular test. The results demonstrate that the ultraviolet irradiation, the cold and the storage of the grapes increase the amount of polyphenols and antioxidant activity modifying the quality of the wine. / Estudos mostraram que a irradiação ultravioleta e o frio em tecidos de plantas apresentam algum efeito sobre o metabolismo de compostos fenólicos. Os polifenóis são um grupo de substâncias presentes no vinho responsáveis por causar uma série de benefícios à saúde do homem e também são importantes na qualidade do vinho. O presente trabalho foi proposto com o objetivo de comparar vinhos provenientes de uvas em variedades viníferas Cabernet Sauvignon e Chardonnay expostas ao frio, irradiação ultravioleta e um posterior armazenamento, verificando seus efeitos na qualidade do vinho através de análises físicoquímicas, bioquímicas e sensoriais. Nas análises físico-químicas da variedade Cabernet Sauvignon foram encontradas pequenas diferenças nos valores de acidez total, porém para os compostos fenólicos, ocorreram variações maiores, apresentando os seguintes valores: Frioirradiado 9723,3 mg EAG, Irradiado 6631,7 mg EAG, Frio-controle 2696,7 mg EAG, Controle 2258,3 mg EAG e Padrão 1150,0 mg EAG. Na determinação da % de inibição da atividade antioxidante também houveram diferenças significativas, refletindo a mesma ordem anterior com os seguintes resultados: Frio-irradiado 97,17%, Irradiado 88.50%, Frio-controle 61,3%, Controle 55,24% e Padrão 41,50%. Para a variedade Chardonnay, os valores das análises físico-químicos mostraram pequenas diferenças no pH, na acidez total e volátil. Para os valores dos compostos fenólicos, a variação foi maior ainda, atingindo os seguintes valores: Frio-irradiado 91,44 mg EAG, Irradiado 76,06 mg EAG, Frio-controle 70,13 mg EAG, Padrão 8,99 mg EAG e Controle 8,94 mg EAG. Foi observado diferenças significativas na determinação da % de inibição da atividade antioxidante, que mostraram os resultados a seguir: Frio-irradiado 91,35%, Irradiado 75,94%, Frio-controle 70,67%, Controle 24,13% e Padrão 9,13%. Na análise sensorial do vinho das duas cultivares, apenas o painel composto de julgadores conhecedores de vinhos distinguiu corretamente as alterações nos vinhos pelo teste triangular. Os resultados demonstram que a irradiação ultravioleta, o frio e o armazenamento das uvas aumentam a quantidade de polifenóis e a atividade antioxidante modificando a qualidade do vinho.

The detection by serology of nematode-transmitted polyhedral viruses (nepoviruses) in grapevines is often unreliable. Nepoviruses were detected by enzyme-linked immunosorbent assay (ELISA) in tissue-cultured and field-grown grapevines. Nepovirus detection in in vitro plants (plantlets) was affected by virus distribution and growth room temperature. The reliability of virus detection in field-grown grapevines was improved when modified grinding buffers were used. Arabis mosaic virus (AMV) was detected by ELISA, for the first time, in in vitro grapevines initiated from field-and screenhouse-grown plants throughout the summer. The virus was not reliably and repeatedly detected in in vitro plantlets grown at 25°C. AMV and grapevine fanleaf virus (GFLV) distribution was not uniform throughout the plantlets. This distribution was affected by the culture room temperature. The best plant parts to sample for virus detection came from the zones of rapidly proliferating shoots. The viruses were sometimes not detected in samples taken from other tissues. Growth room temperature had an important effect on virus detection in plantlets. The highest virus titres were found in plants growing at 15°C. Temperature increases in 5°C steps to 30°C reduced virus titre. AMV became undetectable in nearly all plantlets growing at 30°C for as little as 30 days. Growth at 30°C reduced ELISA absorbance values by 76% after 8 days and after 21 days the values were at 4% of pre-treatment levels. The virus titre dropped below detectable levels in most plantlets. AMV could not be detected in plantlets or rooted explants after being placed in a 30°C treatment for 2 months. Tomato ringspot virus was detected by ELISA, for the first time, in in vitro grapevine plants. The virus was repeatedly detected in in vitro plants growing at 20°C. Under the typical summer conditions experienced at Sidney, B.C., modifying the standard ELISA grinding buffer (0.01 M phosphate buffered saline, pH 7.4, 0.05% Tween-20, 0.2% ovalbumin, 2% polyvinylpyrrolidone) was essential for reliable detection of AMV or GFLV. AMV was reliably detected by ELISA in foliar samples from field or screenhouse plants throughout the summer when the grinding buffer was modified by increasing the pH to at least 8.2 and adding 1% nicotine or 0.15 M phosphate buffered saline. The most reliable results with GFLV were obtained with the nicotine enhanced buffers. In comparison, because of the increased workload associated with growing plants in vitro and the unreliable detection of viruses in these plants, it remained preferable to detect nepoviruses in field plants by ELISA. / Land and Food Systems, Faculty of / Graduate

Orientador: Marco Antonio Tecchio / Resumo: Uvas para processamento de suco têm sido implantadas em regiões não tradicionais de produção para atender o aumento do consumo de suco de uva pela população brasileira. Com isso, o estudo do manejo dessas cultivares é imprescindível para a maior produção e qualidade do suco de uva. O objetivo desse estudo foi avaliar as características produtivas e qualitativas de cultivares de uva para processamento, cultivadas em São Manuel, SP, em dois sistemas de poda: curta e mista. O experimento foi realizado no período de agosto de 2017 a janeiro de 2019. Os tratamentos consistiram em três cultivares de uvas para processamento (BRS Violeta, Bordô e BRS Cora) enxertadas sobre o portaenxerto ‘IAC 572’, as quais foram submetidas a dois manejos de poda: poda curta e poda mista, no sistema de condução em espaldeira. Foram avaliadas a fenologia, curva de maturação, a fertilidade de gemas, a produção e produtividade; massas frescas de cacho e engaço; comprimento e largura de cachos e engaços; número de bagas por cacho; massa fresca, comprimento e largura de bagas; número e massa fresca de sementes por baga; sólidos solúveis, acidez titulável, relação SS/AT; pH, antocianinas monoméricas totais, polifenóis totais, flavonoides. O delineamento experimental em esquema fatorial 3 x 2, sendo três cultivares de uva e dois sistemas de poda (poda curta e poda mista), e seis repetições, totalizando 36 parcelas experimentais. A cultivar BRS Cora apresentou maior duração do ciclo fenológico em relação às ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Viticulture has long belonged to Bratislava. It has been mentioned in archival reports since the middle of the 13th century. The vineyards stretched from Bratislava Castle to Rača and Vajnor. Especially in the last century, large-scale construction of apartment and family houses began to replace vineyards. This trend still persists and developers attract people to live with a view of the city and the proximity of nature, from which, however, they take themselves. The vineyards have been receding for the centuries of the developing city and this historic heritage is falling into oblivion. however, vineyards are not only a reminder of the glorious past, but also of irreplaceable creators of biodiversity and contribute to a better climate for the city. The aim of the diploma thesis is to analyze the retreat of vineyards expanding in Bratislava. Conditions for vine growing and its processing in Bratislava and its surroundings. Subsequently, finding a suitable form and applying the outputs from the analytical part in a specific architectural design.

Botrytis bunch rot, caused by Botrytis cinerea, is a fungal disease that primarily affects the fruit of wine grapes. Infection of fruit consequently results in reduced yields and wine quality. These factors lead to significant economic losses for growers which prompts the implementation of management practices to control the disease. One objective of this study was to evaluate the level of resistance that populations of B. cinerea in the Central Coast region showed to various chemicals. A fungicide assay was conducted to determine resistant phenotypes to six fungicide active ingredients (pyrimethanil, iprodione, fenhexamid, fludioxonil, trifloxystrobin, boscalid). Thirty-five (2020) and 88 (2021) B. cinerea isolates were collected from Santa Maria, Cambria, Paso Robles, and Edna Valley in California and screened for resistance. The frequencies of populations (2020, 2021) showing resistance to each active ingredient were: pyrimethanil (94.3%, 81.8%), trifloxystrobin (97.1%, 100%), boscalid (77.1%, 77.3%), fenhexamid (8.6%, 25%). The majority of isolates were sensitive to iprodione (100%, 100%), fludioxonil (100%, 100%), fenhexamid (88.6%, 75%), and boscalid (22.9%, 22.7%). These results documented the accumulation of resistance in B. cinerea to various fungicides commonly used for Botrytis bunch rot management in California’s Central Coast. Another objective of this study was to determine the effective concentration of the six fungicides that reduces mycelial growth of the fungus by 50% (EC50). Seven B. cinerea isolates in 2020 and ten isolates in 2021 were selected and subjected to a sensitivity screening with serial dilutions of the different fungicide active ingredients. The fungicides found to have the highest EC50 values indicating reduced efficacy for inhibiting B. cinerea growth were Scala® (FRAC 9), Flint® (FRAC 11), and Endura® (FRAC 7). The fungicides found to have the lowest EC50 values indicating higher efficacy for inhibiting B. cinerea growth were Scholar® (FRAC 12) and Rovral® (FRAC 2). The results from this study provided information regarding the accumulated resistance of B. cinerea populations to certain chemical groups and therefore the efficacy of different fungicide active ingredients. This information can be utilized by growers as a tool to enhance and develop fungicide spray programs that effectively manage Botrytis bunch rot in Central Coast vineyards.

No description available.

Thesis (MScAgric)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Botrytis cinerea Pers.: Fr., a pathogen of grapevine (Vitis vinifera L.), moves mainly through conidia by air currents in vineyards which are deposited intermittently on the surfaces of leaves, inflorescences and bunches. Little is known about the relationship between the inoculum dosage in air and incidence of Botrytis bunch rot, and how the relationship is influenced by environmental and host factors. To better understand this relationship, information is needed on the period over which conidia have accumulated, the time they are able to survive and remain infectious, time of symptom expression in relation to conidium arrival at the infection court and host surface wetness. The aims of this study were (i) to estimate the amount of viable B. cinerea occurring in air in vineyards, and at different positions on leaves, inflorescences and bunches of grape at different phenological stages, (ii) to determine the relationships between the number of B. cinerea colonies recorded on spore traps placed in the bunch zone of vines and the incidence of B. cinerea recorded from the different tissues, and (iii) to compare the efficacy of fenhexamid on leaves and inflorescences carrying natural B. cinerea inoculum with those inoculated with dry, airborne conidia. Different techniques were used to detect viable Botrytis cinerea in air currents and on plant material obtained from table (cultivars Dauphine and Waltham Cross in Paarl- and Worcester-district) and wine grape (cultivars Chardonnay, Sauvignon Blanc and Merlot in Stellenbosch- and Malmesbury district) vineyards in the Western Cape province during 2001-02 and 2002-03. For four consecutive days during prebloorn, bloom, pea-size, bunch closure, veraison and harvest, sets of Petri dishes with freshly prepared Kerssies' B. cinerea selective medium (spore traps) were left overnight in the bunch zone of vines. Plant material was collected from the vines on the fourth day. Leaves, infloresence and bunches were treated with paraquat to terminate host resistance and to promote the development of the pathogen on the tissues. The B. cinerea inoculum dosage in air, and the incidence at which the pathogen was detected at various positions on leaves and in bunches normally differed between vineyards. However, the various tests revealed that the pathogen generally occurred in a consistent pattern in air in the bunch zone of vines, on leaves and in bunches from all vineyards. The inoculum dosage in air in the bunch zone of the vine was generally highest during prebioom or during bloom, it decreased at pea size and mostly remained at a very low level at the later growth stages. The estimations of viable B. cinerea residing naturally on leaves and in bunches, showed that their amounts depicted levels occurring in air in the bunch zone of the vine. Necrotic leaves occurring early season in vineyards were identified as an important source of secondary inoculum for dispersal to the developing bunches. Latent infections at the various positions in bunches were few at véraison and harvest. However, due to the necrotrophic ability of the pathogen, extensive berry rot (due to berry-to-berry contact) and thus severe bunch rot developed from a single berry that become symptomatic at the base of the pedicel/berry attachment zone. The B. cinerea occupation pattern explains why Botrytis bunch rot develops mostly from the inner bunch and why disease management strategies should concentrate on the bloom to pre-bunch closure stage and on inhibiting B. cinerea development in the inner bunch during the early part of the season. Thus, to effectively reduce B. cinerea in grapevine, preventative applications are recommended to reduce two primary infection events: (a) between budding and pre-bloom to counteract primary leaf infection; (b) during late bloom or early pea size stage, to reduce the amount of the pathogen on leaves and infloresences and to prevent colonisation of floral debris. A third spray can be applied at bunch closure to reduce the amount of B. cinerea at various positions of the inner bunch, especially for cultivars with tight bunches. The efficacy of fenhexamid on leaves and inflorescences carrying natural B. cinerea inoculum was compared with those inoculated with dry, airborne conidia. Shoots were obtained during late bloom from a vineyard (wine grape cultivar Merlot) in the Stellenbosch region. The shoots were divided into two main groups. One group of shoots was left uninoculated, the other shoots were inoculated by dusting with dry B. cinerea conidia in a settling tower. Before inoculation, equal numbers of shoots in each main group was sprayed with fenhexamid, or left unsprayed. Following inoculation and incubation, shoots of each treatment were divided in two equal groups. The one lot of shoots were rinsed in water. The other lot of shoots were immersed in paraquat solution to terminate host resistance and to promote the development of the pathogen from the tissues. For both uninoculated and inoculated shoots, irrespective of fungicide treatment, leaves remained asymptomatic at both the blade and petiole position for the water rinse treatment. No symptom of B. cinerea decay developed at any of the positions on leaves from shoots sprayed with fenhexamid. Spraying of shoots with fenhexamid completely suppressed B. cinerea infection and symptom expression on both uninoculated and inoculated inflorescens. For inoculated shoots, B. cinerea developed from approximately 50% of the laterals in the water rinse treatment. However, inflorescences rinsed in water remained asymptomatic. The laboratory studies showed that fungicides, if applied properly to shoots and bunches under controlled conditions, effectively reduced the amount of B. cinerea at the various positions on leaves and inflorescence, and prevented infection and symptom expression at bloom. However, these goals are not achieved in vineyards where the fungicides are applied by conventional spraying methods. Therefore, more work is needed to evaluate fungicide application techniques by conventional spraying methods for proper fungicide coverage, and the reduction of B. cinerea in bunches. / AFRIKAANSE OPSOMMING: Botrytis cinerea Pers.: Fr., 'n patogeen van druiwe (Vilis vinifera L.), beweeg hoofsaaklik deur middel van konidia in lugstrome deur die wingerd, en word dan afwisselend op die oppervlakte van die blare, bloeiwyses en trosse gedeponeer. Daar is nog min bekend oor die verhouding tussen die hoeveelheid inokulum in die lug en die voorkoms van Botrytis op die trosse, en hoe die verhouding deur omgewings- en gasheerfaktore beïnvloed word. Ten einde hierdie interaksie beter te verstaan, word inligting benodig oor die tydperk waarin die konidia akkumuleer, die tyd wat hulle oorleef en virulent bly, en die tyd van simptoom-uitdrukking in verhouding tot die verspreiding van die konidia by die infeksie-setel en benatbaarheid van die gasheer-oppervlakte. Die doel van hierdie studie was (i) om die hoeveelheid lewensvatbare B. cinerea wat in die lug voorkom, asook by verskeie posisies op blare, bloeiwyses en trosse by verskillende fenologiese stadiums te kwantifiseer, (ii) om die verhouding tussen die aantal aangetekende B. cinerea kolonies op spoorvangers wat in die trossone van die wingerd geplaas is, en die voorkoms van B. cinerea, aangeteken van verskeie weefsels, te bepaal, en (iii) om die effektiwiteit van fenhexamid op blare en bloeiwyses wat natuurlike B. cinerea inokulum dra, te vergelyk met dié wat met droë, luggedraagde konidia geïnokuleer is. Verskillende tegnieke is gebruik om lewensvatbare Botrytis cinerea in lugstrome en op plantmateriaal van tafeldruiwe (kultivars Dauphine en Waltham Cross In Paarl- en Worcester-distrik) en wyndruiwe (kultivar Chardonnay, Sauvignon Blanc en Merlot in Stellenbosch- en Malmesbury distrik) in wingerde van die Wes-Kaap provinsie gedurende 2001-02 en 2002-03 te kwantifiseer. Petri bakkies met vars voorbereide Kerssies medium, selektief vir B. cinerea (spoorvangers), is vir vier agtereenvolgende dae gedurende vóórblom, blom, ertjiekorrel, trostoemaak, kleurbreek en oes, oornag in die trossone van wingerdstokke in betrokke wingerde, gelaat. Plantmateriaal is op die vierde dag versamel. Blare, bloeiwyses en trosse is met paraquat behandel ten einde die gasheerweerstand af te breek en ontwikkeling van die patogeen op die weefsel te bevorder. B. cinerea inokulum in die lug, en die frekwensie waarby die patogeen op verskeie posisies op blare en in die trosse voorgekom het, het normaalweg tussen wingerde verskil. Die verskeie toetse het getoon dat die patogeen normaalweg in 'n vaste patroon in die lug en die trossones van wingerde, asook op blare en in trosse van alle wingerde voorkom. Die inokulumkonsentrasie in die lug in die trossones van wingerdstokke was normaalweg die hoogste gedurende vóórblom of gedurende blom. Die inokulumdruk het by ertjiekorrel verminder en meestal by 'n 'n baie lae vlak tydens die latere groeistadia gebly. Die bepaling van lewensvatbare B. cinerea wat natuurlik op blare en in trosse gedeponeer is, het getoon dat hul hoeveelhede ooreenstem met vlakke wat in die lug in die trossone van die wingerd voorkom. Nekrotiese blare vroeg in die seisoen is 'n belangrike bron van sekondêre inokulum en speel dus 'n belangrike rol by die verspreiding van Botrytis tussen die ontwikkelende trosse. Latente infeksies by die verskeie posisies in trosse was laag by kleurbreek en oes. Weens die saprofitiese vermoëns van die patogeen, kan uitgebreide korrelvrot (a.g.v. korrel-tot-korrel kontak) en dus ernstige trosvrot, ontwikkel. 'n Enkele korrel kan by die basis van die pedisel/korrel vashegtingsone simptomaties raak, en vandaar na aangrensende korrels versprei. Die B. cinerea kolonisasiepatroon verduidelik waarom Botrytis trosvrot meestal vanaf die binneste tros ontwikkel en waarom siektebeheerstrategieë op die vóórblom- tot blomstadium gekonsentreer moet word, en op die inhibering van B. cinerea ontwikkeling in die binneste tros gedurende die vroeë stadia van die seisoen. Dus, om B. cinerea effektief tydens die twee primêre infeksie stadiums in wingerde te verminder, kan voorkomende toedienings aanbeveel word: (a) tussen knopvorming en vóórblom om primêre blaarinfeksie te verhoed; (b) gedurende láátblom en vroeë ertjiekorrel om die hoeveelheid inokulum op die blare en bloeiwyses te verminder, en die kolonisasie van blomdebris te voorkom. 'n Derde toediening kan tydens trostoemaak aangewend word om B. cinerea by verskeie posisies in die binneste tros te verminder, veral by kultivars met digte trosse. Die effektiwitiet van fenhexamid op blare en bloeiwyses waarop natuurlike B. cinerea inokulum voorkom is vergelyk met dié wat met droë, luggedraagde konidia geïnokuleer is. Lote is vanaf 'n wingerd (wyndruif kultivar Merlot) in die Stellenbosch distrik tydens láátblom verkry en in twee hoofgroepe verdeel. Die een groep lote is geïnokuleer deur droë B. cinerea konidia in 'n afsettingstoring te strooi, terwyl die ander groep nie geïnokuleer is nie. Vóór inokulasie, is die helfte van die lote in elke groep met fenhexamid behandel, terwyl die ander helfte onbehandeld gelaat is. Ná inokulasie en inkubasie, is lote van elke behandeling verder in twee eweredige groepe verdeel. Die een groep lote is in water gespoel, terwyl die ander groep lote in 'n paraquatoplossing gedompel is om die gasheerweerstand te verwyder, en die ontwikkeling van die patogeen vanuit die weefsels te bevorder. Vir die waterspoelbehandeling van beide ongeïnokuleerde en geïnokuleerde lote, ongeag van die fungisiedbehandeling, het die blare asimptomaties by beide die bladoppervlakte en blaarsteelposisie gebly. Geen simptome van B. cinerea verrotting het by emge van die blaarposisies van die lote, met fenhexamid gespuit, ontwikkel nie. Die spuit van die lote met fenhexamid het die B. cinerea infeksie en die simptoomontwikkeling op beide die ongeïnokuleerde en geïnokuleerde bloeiwyses heeltemalonderdruk. By die geïnokuleerde lote, het B. cinerea vanaf ongeveer 50% van die laterale in die waterspoelbehandeling ontwikkel, alhoewel, bloeiwyses wat in water afgespoel is, heeltemal asimptomaties gebly het. Laboratoriumstudies het getoon dat fungisiedes, indien korrek toegedien op lote en trosse onder gekontroleerde toestande, tot effektiewe vermindering van B. cinerea getalle by die verskillende posisies op blare en bloeiwyses lei, en infeksie en simptoomuitdrukking tydens blom voorkom. Weens die feit dat die doelwitte nie behaal kan word in wingerde waar die fungisiede deur konvensionele spuitmetodes toegedien is nie, moet meer studies gedoen word om fungisied toedieningstegnieke, by konvensionele spuitmetodes, VIr deeglike fungisiedbedekking en die vermindering van B. cinerea in trosse, te evalueer.

Dissertation (PhD(Agric)) -- Stellenbosch University, 2005. / ENGLISH ABSTRACT: Due to increased consumer demand for products labelled by origin, and the requirement that these labels are a guarantee of both quality and product character, there is an increasing global focus on delimitation of denominations of origin. The integrity of denominations of origin and their defensibility can be ensured through the use of terroirs as a basis for delimitation. The aims of this study were to establish the dominant environmental criteria that affect the viticultural behaviour and wine character of two important cultivars (Cabernet Sauvignon and Sauvignon blanc) in the Stellenbosch Wine of Origin District, to use an appropriate methodology to identify viticultural terroirs in this district based on these criteria and with the use of a geographic information system, and finally to use these viticultural terroirs to identify denominations of origin within the same area. A terroir can be defined as a grouping of homogenous environmental units, or natural terroir units, based on the typicality of the products obtained. Identification and characterisation of terroirs depends on knowledge of environmental parameters, the functioning of the grapevine and the characteristics of the final product. Field studies, resulting in point data, are necessary to investigate the functioning of the grapevine but in order for this information to be of use within zoning studies it must be placed in a spatial context. As a first phase in data acquisition, the Stellenbosch Wine of Origin District was characterised and natural terroir units were identified using existing digital data and a geographic information system. A natural terroir unit (NTU) can be defined as a unit of land that is characterised by relatively homogenous topography, climate, geological substrate and soil. A total of 1389 NTUs were identified in the Stellenbosch Wine of Origin District (84 537 ha). The identified NTUs were homogenous with respect to terrain morphological unit, altitude, aspect and soil type. Each of the identified units was further described with respect to the extent of the expected sea breeze effect and, for certain of the soil types, the associated parent material. As a second phase of data acquisition, a network of plots of Sauvignon blanc and Cabernet Sauvignon were delimited in commercial vineyards in proximity to weather stations and their viticultural and oenological response monitored for a period of seven years. Regression tree analyses were performed on the complete data set and the relative importance of the environmental and management related variables determined for each dependent variable. Excepting for scion clone, which had a high relative importance for bunch mass of Sauvignon blanc and yield to pruning mass index of Cabernet Sauvignon, no other non-environmental variable included in the analyses appeared to have a strong effect on grapevine performance and wine character. The performance of Cabernet Sauvignon was affected by the potassium content of the subsoil and the climate of the season. The performance of Sauvignon blanc appeared to be related to soil texture, wind exposure and temperature, both during the green berry growth stage and the month prior to ripening. From the results presented, it appears that environmental parameters have an overriding effect on the performance of both Cabernet Sauvignon and Sauvignon blanc, but that these two cultivars react differently to environmental stimuli. A knowledge-driven model used the rules generated in the regression tree analyses to directly classify natural terroir units with respect to expected response of Cabernet Sauvignon and Sauvignon blanc in the Stellenbosch Wine of Origin District. The natural terroir units were thus grouped into terroir units that were homogenous with respect to predicted viticultural and oenological response for each cultivar. The use of representative sites to determine the response of the grapevine to its environment is time consuming and costly and limits terroir studies to research related investigations. Vineyard managers were therefore surveyed with respect to the functioning of established Sauvignon blanc vineyards in the Stellenbosch Wine of Origin District in an attempt to obtain the necessary data. Comparison of the data generated with these questionnaires to measured data in commercial vineyards suggested that the vineyard managers were able to characterise the performance of vineyards with respect to vigour, signs of drought stress and yield. Each vineyard was mapped and the responses were linked to modelled environmental variables. Classification and regression trees were used to construct decision trees, which could be applied to environmental data in a geographic information system to determine viticultural terroirs for production of Sauvignon blanc. These terroirs, although fewer, were comparable to those generated using field data. Data gathered during terroir studies, and the identified viticultural terroirs for Cabernet Sauvignon and Sauvignon blanc, were used to revisit the boundaries of the Stellenbosch Wine of Origin District and the Simonsberg-Stellenbosch ward. Modifications were proposed based on expected wine characteristics. Boundaries for two new wards in the Helderberg basin were proposed. It was also possible to identify vineyards within a ward for the production of terroir specific wines. / AFRIKAANSE OPSOMMING: Toenemende verbruikersaanvraag vereis produkte waarvan die etikette nie net die oorsprong aandui nie, maar ook kan dien as ‘n waarborg vir die produk se kwaliteit en kenmerkendheid. Hierdie tendens verklaar die toenemende wereldwye fokus op afgebakende areas van oorsprong. Die integriteit van die afgebakende areas van oorsprong sowel as hul verdedigbaarheid kan gewaarborg word deur terroirs as basis vir afbakening te gebruik. Die doelstellings van die studie was om die oorheersende omgewingseienskappe wat wingerdprestasie en wynkarakter van twee belangrike cultivars, naamlik Cabernet Sauvignon en Sauvignon blanc, in die Stellenbosch Wyn van Oorsprongsdistrik bemvloed, te bepaal; tweedens om ‘n toepaslike metodologie te gebruik om terroirs in die die distrik te bepaal wat gebaseer is op die geidentifiseerde omgewingseienskappe met die gebruik van ‘n geografiese inligtingstelsel; en, ten slotte, om hierdie terroirs vir wingerbou te gebruik om afgebakende areas van oorsprong in dieselfde omgewing te identifiseer. ‘n Terroir kan gedefinieer word as ‘n samestelling van homogene omgewingseenhede, of natuurlike terroir-eenhede (NTE), wat gebaseer word op die kenmerkende eienskappe van die produkte wat daaruit verkry word. Identifisering en karakterisering van terroirs sal afhang van kennis van die omgewingsparameters, die funksionering van die wingerdstok en die eienskappe van die finale produk. Veldstudies waaruit puntdata verkry word, is noodsaaklik om die funksionering van die wingerdstok te ondersoek. Dit is egter noodsaaklik om eers hierdie inligting in ruimtelike konteks te plaas alvorens die inligting vir soneringstudies gebruik kan word. As 'n eerste fase van datagenerering, was die Stellenbosch Wyn van Oorsprongsdistrik gekarakteriseer en NTE’s geidentifiseer deur gebruik te maak van bestaande digitale data en ‘n geografiese inligtingstelsel. ‘n NTE kan gedefinieer word as ‘n landseenheid wat gekarakteriseer word deur ‘n relatiewe homogene topografie, klimaat, geologiese substraat en grondtipe. ‘n Totaal van 1389 NTE’s is geidentifiseer in die Stellenbosch Wyn van Oorsprongsdistrik (84 537 ha). Die geidentifiseerde NTE’s was homogeen met betrekking tot die terrein morfologiese eenheid, hoogte bo seespieSI, hellingsaspek en grondtipe. Elk van die geidentifiseerde eenhede was verder beskryf volgens die omvang van die seewindinvloed en, vir toepaslike grond tipes, die geassosieerde moedermateriaal. As ‘n tweede fase van datagenerering is ‘n netwerk van persele van Cabernet Sauvignon en Sauvignon blanc afgebaken binne bestaande kommersiele wingerde in die nabyheid van weerstasies. Hul wingerd- en wynkundige respons is vir ‘n periode van sewe jaar gemonitor. Regressieboomanalises is gebruik om die volledige stel data te analiseer en om die relatiewe belang van omgewings- en bestuurspraktykverbonde veranderlikes te bepaal. Die bostokkloon (wat 'n hoe relatiewe belang vir die trosmassa van Sauvignon blanc en die oes- tot snoeimassa verhouding van Cabernet Sauvignon het) is die enigste van die nie-omgewingsparameter wat ‘n sterk invloed op wingerdprestasie of wynkarakter blyk te he. Die prestasie van Cabernet Sauvignon is beTnvloed deur die kaliuminhoud van die ondergrond sowel as die seisoensklimaat. By Sauvignon blanc het dit voorgekom of die prestasie verband hou met grondtekstuur, windblootstelling en temperatuur tydens die groen fase van korrelgroei sowel as die maand voor rypwording. Alhoewel dit blyk uit die resultate dat omgewingsparameters 'n oorheersende invloed op die prestasie van beide Cabernet Sauvignon en Sauvignon blanc uitoefen, reageer die twee cultivars verskillend op omgewingsprikkels. ‘n Kennisgedrewe model waarvan die riglyne uit resultate van die regressieboomanalise saamgestel is, word gebruik om NTE direk te klassifiseer ten opsigte van die verwagte respons van Cabernet Sauvignon en Sauvignon blanc in die Stellenbosch Wyn van Oorsprongsdistrik. Die NTE is dus gegroepeer om terroir eenhede te vorm wat homogeen was ten opsigte van die verwagte wingerd- en wynkundige respons vir elke cultivar. Die gebruik van verwysingspersele om die respons van die wingerdstok teenoor sy onmiddelike omgewing te bepaal, is tydrowend en duur en beperk sodoende terroir studies tot navorsing. Gevolglik is ‘n opname onder wingerdbestuurders gemaak om inligting oor die prestasie van Sauvignon blanc in die Stellenbosch Wyn van Oorsprongsdistrik in te win en sodoende die nodige data te verkry. Na vergelyking van die ingewinde data, wat uit die opname verkry is, met gemete data vanaf kommersiele wingerde, kon afgelei word dat wingerdbestuurders by magte is om die prestasie van wingerde ten opsigte van groeikrag, tekens van droogtestres en opbrengs te karakteriseer. Elke wingerd is gekarteer en die respons is gekoppel aan die gemodeleerde omgewingsparamters. Klassifikasie en regressiebome is gebruik om besluitnemingsmodelle saam te stel wat toegepas kon word op omgewingsdata in ‘n geografiese inligtingstelsel om terroirs vir die produksie van Sauvignon blanc te bepaal. Hierdie terroirs, alhoewel minder, was vergelykbaar met die wat gegenereer was met behulp van veldstudies. Data verkry met terroirstudies, sowel as gei'dentifiseerde terroir-eenhede, was gebruik om die grense van die Stellenbosch Wyn van Oorsrongsdistrik en die Simonsberg-Stellenbosch wyk te herbepaal. Voorgestelde modifiserings was gebaseer op verwagte wyneienskappe. Grense vir twee nuwe wyke in die Helderbergkom is voorgestel. Dit was ook moontlik om wingerde binne ‘n wyk te identifiseer vir die produksie van terroir-spesifieke wyne.

Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / South Africa is the eighth largest wine producing country in the world and face stiff competition on the world market. Cabernet Sauvignon is the most planted red cultivar in the world as well as in South Africa and can be seen as the wine by which countries are judged. The aim of this study was to investigate suitable, practical maturity parameters or combinations thereof to determine the optimal time to harvest Cabernet Sauvignon grapes under South African conditions. The following parameters were investigated during this study: seed lignification, maturity indexes, anthocyanin concentration per berry, sensory criteria (grape skins tasting and wine) and phenolic content. Berry development in four Cabernet Sauvignon vineyards in different South African winegrowing areas were investigated over the 2003, 2004 and 2005 seasons. The first parameter to be investigated was seed lignification percentages. Seasonal differences at commercial harvest were observed with values of 2004 varying between 73% and 91% compared to 59% and 80% for the 2003 and 2005 seasons but commercial harvest was two weeks later during the 2004 season. During this study it was found that seeds never reached 100% lignification for Cabernet Sauvignon as was found in previous work to indicate grape maturity. The development of anthocyanins also peaked well before the maximum seed lignification was reached. It therefore appears that seed lignification is not suitable for the determination of grape maturity for Cabernet Sauvignon grapes under South African conditions. The second parameter to be investigated was maturity indexes (Balling / Titratable Acidity (TA), Balling × pH, Balling × pH2). The best wine values were used to determine the optimal maturity index values. Morgenster was the only vineyard to consistently give values that corresponded to previously reported data (index values). Anhöhe and Plaisir de Merle reported higher maturity values than that reported in literature and seasonal variation was observed. Maturity index values for the best wines varied between 88 and 101 (Balling × pH) for Anhöhe during 2003 and 2005 seasons, but increased too between 97 and 107 (Balling × pH) for 2004. The maturity index values were found to be vineyard and season dependant, with warmer areas reaching higher values. From this study it appears that maturity index values as a singular maturity parameter does not give a good indication of berry maturity in all seasons or vineyards. Thirdly, the berry anthocyanin concentration (mg / berry and mg / g berry) were investigated and comparable trends were found between the four vineyards. However vineyards in warmer, drier regions (Anhöhe) tended to have higher anthocyanin concentrations per gram berry. The more vigorous vineyard of Morgenster consistently exhibited a higher anthocyanin concentration per berry. This can be explained by the ratio of skin to pulp between small berries (Anhöhe, 0.95 g - 2004) and larger berries South Africa is the eighth largest wine producing country in the world and face stiff competition on the world market. Cabernet Sauvignon is the most planted red cultivar in the world as well as in South Africa and can be seen as the wine by which countries are judged. The aim of this study was to investigate suitable, practical maturity parameters or combinations thereof to determine the optimal time to harvest Cabernet Sauvignon grapes under South African conditions. The following parameters were investigated during this study: seed lignification, maturity indexes, anthocyanin concentration per berry, sensory criteria (grape skins tasting and wine) and phenolic content. Berry development in four Cabernet Sauvignon vineyards in different South African winegrowing areas were investigated over the 2003, 2004 and 2005 seasons. The first parameter to be investigated was seed lignification percentages. Seasonal differences at commercial harvest were observed with values of 2004 varying between 73% and 91% compared to 59% and 80% for the 2003 and 2005 seasons but commercial harvest was two weeks later during the 2004 season. During this study it was found that seeds never reached 100% lignification for Cabernet Sauvignon as was found in previous work to indicate grape maturity. The development of anthocyanins also peaked well before the maximum seed lignification was reached. It therefore appears that seed lignification is not suitable for the determination of grape maturity for Cabernet Sauvignon grapes under South African conditions. The second parameter to be investigated was maturity indexes (Balling / Titratable Acidity (TA), Balling × pH, Balling × pH2). The best wine values were used to determine the optimal maturity index values. Morgenster was the only vineyard to consistently give values that corresponded to previously reported data (index values). Anhöhe and Plaisir de Merle reported higher maturity values than that reported in literature and seasonal variation was observed. Maturity index values for the best wines varied between 88 and 101 (Balling × pH) for Anhöhe during 2003 and 2005 seasons, but increased too between 97 and 107 (Balling × pH) for 2004. The maturity index values were found to be vineyard and season dependant, with warmer areas reaching higher values. From this study it appears that maturity index values as a singular maturity parameter does not give a good indication of berry maturity in all seasons or vineyards. Thirdly, the berry anthocyanin concentration (mg / berry and mg / g berry) were investigated and comparable trends were found between the four vineyards. However vineyards in warmer, drier regions (Anhöhe) tended to have higher anthocyanin concentrations per gram berry. The more vigorous vineyard of Morgenster consistently exhibited a higher anthocyanin concentration per berry. This can be explained by the ratio of skin to pulp between small berries (Anhöhe, 0.95 g - 2004) and larger berries (Morgenster, 1.82 g – 2004). Wine colour density (A420+A520) followed the same trend as the anthocyanin concentrations of the homogenate. Grape skins (G) were used to make an artificial wine that was evaluated by an expert panel to determine the development of the grapes. Wines (W) made from sampled batches were also evaluated by an expert panel for: colour intensity, vegetative, red berry, black berry with spice, acidity, astringency and general quality. Vegetative aromas and acidity decreased and red and black berry with spice increased during ripening for both berries and wine. Colour intensity also increased, corresponding to an increase in perceived general quality score. Correlations between general quality of both the grape skins tasting and wines were investigated. Balling showed a strong correlation with general quality of the grape skins tasting (r = 0.76; p = 0.00) but not as strongly with subsequent wines (r = 0.57; p = 0.00). Anthocyanin concentration (mg / g berry) of the berries (r = 0.36; p = 0.00), perceived colour intensity of grapes (r = 0.69; p = 0.00) and wine (r = 0.84; p = 0.00) correlated with general wine quality. The tasting panel identified wines that were statically better than the rest for each season and vineyard. Maximum berry anthocyanin concentration coincided with wines rated as the best by the tasting panel. More than one wine was identified during the maximum anthocyanin peak that did not differ statistically from the best wine. It appears from this study that a window period exists at the maximum anthocyanin peak, where wines of comparable quality, but different style, can be produced. Principal component analysis (PCA) was used to determine the least number of suitable parameters that could distinguish between unripe and ripe grapes in order to establish a grape maturity model. These differences were successfully described by Balling, TA, pH, potassium (K+), tartaric and malic acid. Anthocyanin concentration could further distinguish between ripe and overripe grapes in the model. From these parameters the minimum and maximum values were used to construct a universal ripeness model containing data from all four vineyards. Variation between the four vineyards caused too much overlapping in the universal model data as the vineyards were situated in different climatic regions according to the Winkler temperature model. On a per vineyard basis this did not occur to the same extend. The best rated Cabernet Sauvignon wines correlated strongly with soluble solid content; colour and quality perceptions of grapes, but large seasonal differences resulted in larger grape compositional variances than that of the individual vineyards in the different climatic zones. This illustrated the difficulty of pinpointing a specific parameter to indicate optimal ripeness. From this study it is clear that a universal maturity model for Cabernet Sauvignon berries is not attainable at present, but individual vineyard models shows the most potential. A preliminary study into the differences of the phenolic composition was done using reverse phase high performance liquid chromatography (RP-HPLC) on the homogenate and wine. Malvidin-3-glucoside and total anthocyanins followed comparable trends to that found for the Iland method. Strong correlations (r > 0.9) were found between the malvidin- 3-glucoside and malvidin-3-glucoside-acetate and p-coumarate; this was also true for the total anthocyanins in both homogenate and wine. Wines identified by a tasting panel to be the best quality, corresponded with the maximum anthocyanin concentration (mg / L) peak in the homogenate. Dense canopies at the Morgenster vineyard over the three seasons lead to lower total anthocyanin and quercetin-3-glucuronide concentrations compared to the Anhöhe and Plaisir de Merle vineyards. The shading of bunches by the dense canopy most likely contributed to this. Catechin, epicatechin, proanthocyanidin and polymeric phenol concentrations decreased significantly from veraison until harvest. Seasonal differences were noted in the four vineyards. No correlations could be found between the general wine quality and the phenolic compounds, but a weak trend was observed for total anthocyanins in the homogenate. A trend was found with the total flavan-3-ol to anthocyanin ratio determined by RP-HPLC analysis of the grape homogenates (r = 0.40, p = 0.00). This ratio varied between 1 and 3 for the wines rated as being the best quality. Phenols by themselves do not give a clear indication of optimal harvest time. From this study it appears that no single parameter could consistently indicate optimal ripeness over the seasons or per vineyard, but the maximum berry colour (anthocyanin concentration) did give an indication of optimal harvesting time. It is clear that a combination of parameters could predict the optimal time more precisely as with the above mentioned model but more research is needed to this end.

Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2006. / The assessments of grape and wine quality are complex issues and the wine industry needs more objective analysis of grape and wine quality. The standard quality assessment protocol for grading grapes at most wine cellars in South Africa is based on viticultural practices and the determination of chemical parameters such as ºBrix, pH and titratable acidity (TA). Grape juice indices calculated by formulae such as ºBrix/pH, TA/pH, ºBrix/TA, ºBrix x (pH)2 have been used in the past but these approaches have had limited success. It was shown that the total anthocyanins and total phenolics of red grapes correlate with wine quality and provide additional objective measures of grape quality. Most methods for the quantification of total anthocyanins and total phenolics are complex and time consuming and therefore not easily implemented in the routine laboratory environment. Fourier transform infrared spectroscopy (FT-IR) is widely used in South African laboratories for the routine quantification of wine and grape parameters but the commercial calibration models supplied for the quantification of grape total anthocyanins and phenolics are not satisfactory. The focus of this study was to develop new FT-IR calibration models for the quantification of total anthocyanins and phenolics of grapes and to use the generated data during a preliminary evaluation of the implementation of these parameters as part of the grape quality control protocol at a commercial winery in South Africa. The potential of Fourier transform infrared spectroscopy (FT-IR) for the rapid quantification of total anthocyanins and total phenolics in red grapes was investigated and evaluated for prediction accuracy with independent validation sets. The design of calibration sets aimed at capturing most of the variation due to vintage (2004 and 2005), cultivar (Cabernet Sauvignon, Merlot, Pinotage, and Shiraz) and sugar concentration. Best prediction accuracies were obtained for calibration sets using grapes from a single vintage or cultivar or approximately the same sugar concentration. The highest prediction accuracies were obtained for total anthocyanins calibration sets of grapes with sugar concentrations ≥ 23.5ºBrix (SEP = 0.13 mg/g; R2 validation set = 0.77) and for total phenolics calibration sets of grapes with sugar concentrations < 23.5ºBrix (SEP = 0.13 OD280/g; R2 validation set = 0.74). Strong correlations were found between the spectral data and the total anthocyanins (SEP = 0.12 mg/g; R2 validation set = 0.84) and total phenolics concentration data (SEP = 0.10 OD280/g; R2 validation set = 0.76) for 2005 Merlot calibration sets indicating that the FT-IR spectra captured most of the variation. Overall the RPD (ratio of the standard deviation of the reference data to the standard error of prediction) values of all calibration models were below 3 indicating that calibration models are fit for screening purposes. Spectroscopic absorbance at 280 nm is not specific enough for the quantification of total phenolics and the use of an alternative reference method such as high performance liquid chromatography (HPLC) will be considered in the future. Principal component analysis (PCA) revealed that the major sources of variation in the FT-IR spectra of grapes could be ascribed to vintage and grape sugar concentration and this had an effect on the accuracy of the analytical data generated when using FT-IR spectroscopy. This report is the first to our knowledge where FT-IR has been used for the quantification of total anthocyanins and phenolics of grapes. The evaluation of the reference laboratory protocol for the quantification of total anthocyanins and total phenolics in grapes were evaluated in Chapter 4 and emphasized the importance of meticulous laboratory practices to obtain reliable reference data for calibration purposes. This large scale investigation of the total anthocyanins and phenolics concentrations in grapes is the first of its kind in South Africa and a quantitative database containing analytical data of the anthocyanins and total phenolics concentrations of 692 grape samples representing a wide range of grape maturities of Vitis vinifera cultivars Cabernet Sauvignon, Merlot, Pinotage and Shiraz from the 2004 and 2005 vintages was established based on the reference values. The data were used in a preliminary investigation of the implementation of total anthocyanins and total phenolics concentrations as part of grape quality classification at a commercial South African winery (Chapter 5). The results showed that the total anthocyanins and total phenolics concentration in grapes increased with increasing grape maturity (measured as sugar concentration). ANOVA and post-hoc analysis (Bonferroni testing) revealed significant differences between the total anthocyanins and total phenolics concentrations of the four Vitis vinifera cultivars investigated. Grapes harvested earlier in the season had significantly higher (p≤0.05) total anthocyanins and total phenolics concentrations than grapes harvested later in the season. This implies that grapes harvested earlier in the harvest season could produce wines with higher quality. Grapes from regularly irrigated vineyards had lower total anthocyanins and total phenolics concentrations compared to dryland vineyards. The current grape grading system in use at the industrial cellar did not correlate well with the total anthocyanins and total phenolics concentrations of grapes which highlighted the need for the inclusion of more objective measures during grape grading. The information captured in the database can be used as a starting point to establish profiles of the typical anthocyanins and total phenolics of South African grapes and data from more vintages should be included and continually updated. These findings highlight the important contribution of the results obtained in this preliminary study for the incorporation of total anthocyanins and phenolics concentrations as objective parameters of grape quality. Finally multivariate data analysis of the FT-IR spectra revealed important information regarding factors (both physical and chemical) that contribute to the variation of the spectra. The main variation between the 2004 and 2005 samples can probably be interpreted in terms of the water content of the samples.