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.

The effects of varying levels of sulphur dioxide (SO₂) on the cold maceration process was investigated with Pinot noir (Vitis vinifera L.) wine. The effects of these varying levels on the wines composition and colour parameters were examined. Cold maceration is a technique whereby grapes are crushed and placed at low temperatures (4 - lO°C) in the presence 50 - 150 mgL⁻¹ SO₂. This process is believed to provide a medium for the extraction of water soluble phenolic compounds, rather than the alcoholic extraction employed in normal fermentations. The extraction of these phenolic compounds was monitored from the juice through to six months of bottle age. The changes were measured using both Spectrophotometric and High Performance Liquid Chromatographic (HPLC) procedures. Cold maceration wines were found to be not significantly different to the control wine in all compositional parameters other than titrateable acidity which was found to be less than the control for all the cold maceration wines. The unsulphured cold maceration wine was not significantly different from the control wine in any of the spectral measurements except natural degree of ionisation, in which it was higher, and total phenolics, in which it was lower. These results indicate that the cold maceration process alone does not alter the extraction of phenolic compounds. The HPLC analysis of the wine confirmed the spectral results indicating that their were no significant differences in the levels of extraction of anthocyanins. The sulphured cold maceration wines were significantly greater than the control in visible colour, colour density, total anthocyanins, natural degree of ionisation, ionised anthocyanins and total phenolics. These results followed similar patterns with wine ageing, at six months these wines were still significantly greater in all the measurements apart from natural degree of ionisation. The results for the sulphured cold maceration wines indicates that SO₂ is acting as a solvent for the extraction of phenolic compounds including anthocyanins. The 50 mgL⁻¹ SO₂ cold maceration wine had similar colour and phenolic content to the 100 mgL⁻¹ SO₂ cold maceration wine at bottling, at six months the 50 mgL⁻¹ SO₂ cold maceration wine still retained a similar colour to the 100 mgL⁻¹ SO₂ cold maceration wine but had vastly reduced anthocyanin content. This indicates that for the grapes utilised in this study the most appropriate level of addition at cold maceration would be 50 mgL⁻¹ of SO₂. With grapes of differing phenolic content the level of addition required will vary.

Two pre-fermentation treatments were investigated in Pinot noir (Vitis vinifera L.) wines. The effects of cold maceration and carbonic maceration on the wines' composition, colour parameters and sensory properties were examined. Cold maceration is a winemaking technique used to increase non-alcoholic extraction in Pinot noir winemaking prior to fermentation. It involves holding crushed grapes with approximately 100-150 mg l⁻¹ SO₂ at low temperatures and is thought to increase the colour, aroma and flavour of the resulting wines. Carbonic maceration uses whole bunches that have undergone anaerobic metabolism to produce characteristically fruity and spicy wines. Pre-fermentation cold maceration produces wines that are higher in titratable acidity and monomeric anthocyanin content, but lower in colour density, hue and polymeric pigments. Reducing the maceration temperature below 10°C has little effect. Carbonic maceration produces wines that are lower in titratable acidity, monomeric anthocyanin content, and colour density but are higher in colour hue and amount of polymeric pigments. Quantitative descriptive analysis was used to define the effects of these pre-fermentation maceration treatments on the sensory characteristics of the resulting wine. Trained panel members found that there were no discernable sensory differences in the compositional parameters despite measurable chemical differences. Investigation into the aroma and flavour characteristics of the wines found that carbonic maceration produces wines that were lower in berry aroma and higher in acetate or ester-type aromas than the control wines. These wines were considered to have specific raspberry, floral, sugar, cherry and chemical aromas. This chemical note was also observed in the flavour of the carbonic maceration wines. The temperature of the cold maceration process has no major effect on the aroma and flavour of the resulting wines. However, the 10°C maceration was higher in woody/tobacco aroma than the 4°C maceration, and the 10°C treatment was also higher in bitter flavour than all the other treatments. Cold maceration wines were found to have specific mixed berry, dried fruit and sweet-oxidised aroma characters, together with a blackberry flavour note.

Vineyards in New Zealand suffer bird damage caused by several avian species, including blackbirds and silvereyes. The introduced European Blackbird takes whole grapes which reduces yield. The self-introduced Australasian Silvereye pecks on grapes, leaving them on the vine to be further attacked by fungi and bacteria, and the subsequent off-odours can cause grapes to be refused by the winery or to suffer a price-reduction. Bird control methods remain primitive and largely ineffective during the long ripening period of wine grapes. An ecologically sound method to manage and reduce bird pressure requires deeper understanding of why some birds eat grapes, especially since grapes are not particularly nutritious. This work investigated the extent to which blackbirds and silvereyes are attracted by various compounds in ripening grapes. Since in natural grapes these compounds develop and change simultaneously, I developed an artificial grape in which a single parameter could be investigated. Artificial grapes (and sometimes nectar) were presented on a bird feeder table and the responses of birds to hexose sugars, the aromas 2-3-isobutylmethoxypyrazine and geraniol, tartaric and malic acids, grape tannins, and purple and green colour were recorded on timelapse video and analysed.

Heat induced protein haze is a common problem in white wine. Grape derived pathogenesis related proteins slowly denature and aggregate during wine storage and this gives rise to light dispersing haze. Protein haze formation is currently prevented by removing proteins using bentonite, an aluminium silicate clay, but this method has drawbacks. A potential alternative or complementary method is the use of haze protective factors ( HPF ), specific mannoproteins from Saccharomyces cerevisiae that visually reduce protein haze. Hpf1p was originally isolated from Muscat Gordo Blanco wine and Hpf2p from a synthetic grape juice ferment. Based on partial amino acid sequences, putative structural genes, HPF1 and HPF2, for these proteins were identified. HPF1 has a homologue, HPF1 ', ( 71 % similarity ) in S. cerevisiae. Sequence analysis suggests that Hpf1p, Hpf1 ' p and Hpf2p are localised to the cell wall or plasma membrane. This study aimed to determine the biological function of the HPF genes in S. cerevisiae. HPF overexpression and deletion strains were constructed and analysed for cell wall related phenotypes. Under a number of conditions, including cold temperature and ethanol stress, the hpf1 Δ hpf1 ' Δ strain was more tolerant than the wild type strain. However, mating efficiency of the hpf1 Δ hpf1 ' Δ strain was significantly less than the wild type strain and this was found to be correlated with the persistence of a septum between the mating partners. The decreased mating efficiency was also mating type specific, only occurring in MAT α cells. This study also aimed to establish conclusively that the HPF genes do indeed encode proteins with haze protective properties. Haze protective activity of the material from ferment supernatants was assessed. Material from the HPF deletion strains exhibited significantly less haze protective activity than the wild type. Moreover, material derived from HPF1 and HPF1 ' overexpressors was more active than material from the wild type. A 6xHis - tagged Hpf2p was expressed and purified using immobilised metal affinity chromatography. This Hpf2p had significant haze protective activity. Modification of N - glycans of 6xHis - Hpf2p by Endoglycosidase H decreased its haze protective activity.visually reduce protein haze. Hpf1p was originally isolated from Muscat Gordo Blanco wine and Hpf2p from a synthetic grape juice ferment. Based on partial amino acid sequences, putative structural genes, HPF1 and HPF2, for these proteins were identified. HPF1 has a homologue, HPF1 ', ( 71 % similarity ) in S. cerevisiae. Sequence analysis suggests that Hpf1p, Hpf1 ' p and Hpf2p are localised to the cell wall or plasma membrane. This study aimed to determine the biological function of the HPF genes in S. cerevisiae. HPF overexpression and deletion strains were constructed and analysed for cell wall related phenotypes. Under a number of conditions, including cold temperature and ethanol stress, the hpf1 Δ hpf1 ' Δ strain was more tolerant than the wild type strain. However, mating efficiency of the hpf1 Δ hpf1 ' Δ strain was significantly less than the wild type strain and this was found to be correlated with the persistence of a septum between the mating partners. The decreased mating efficiency was also mating type specific, only occurring in MAT α cells. This study also aimed to establish conclusively that the HPF genes do indeed encode proteins with haze protective properties. Haze protective activity of the material from ferment supernatants was assessed. Material from the HPF deletion strains exhibited significantly less haze protective activity than the wild type. Moreover, material derived from HPF1 and HPF1 ' overexpressors was more active than material from the wild type. A 6xHis - tagged Hpf2p was expressed and purified using immobilised metal affinity chromatography. This Hpf2p had significant haze protective activity. Modification of N - glycans of 6xHis - Hpf2p by Endoglycosidase H decreased its haze protective activity. / Thesis (Ph.D.)--School of Agriculture and Wine, 2003.

Viticultural practices such as trunk girdling and shoot topping along with defoliation, shading and node number per vine treatments were used to alter the carbohydrate physiology of mature Chardonnay grapevines growing in the cool climate of Canterbury, New Zealand. The timing of vine defoliation in the season previous to fruiting decreased concentrations of over-wintering carbohydrate reserves (mostly starch) in both the trunks and roots of grapevines. Roots were particularly sensitive, with defoliation as early as 4 weeks after bloom in the previous season reducing starch concentrations to 1.5%Dwt at bud burst compared with 17%Dwt in non-defoliated vines. In contrast, partial vine defoliation as early as bloom in the previous season reduced root starch concentrations to 4-7%Dwt at bud burst compared with 15%Dwt in non-defoliated vines. Vine shading and trunk girdling treatments at bloom in the previous season, resulted in small reductions in root starch concentrations (16%Dwt) compared with non-shaded and non-girdled vines (19%Dwt), but shoot topping did not. Study across three growing seasons established that higher concentrations of over-wintering trunk and root carbohydrate reserves were associated with warmer and sunnier weather in the previous growing season. Individual shoot leaf removal at either the beginning or towards the end of the inflorescence initiation period, reduced shoot starch concentrations to 3-6%Dwt compared with 11 %Dwt for no leaf removal, such reductions persisted through to the following season. Shoot topping at the start of the initiation period had no effect on shoot carbohydrate accumulation, but trunk girdling temporarily increased shoot starch concentrations during the first 31 days after treatment. Reductions in over-wintering trunk and root carbohydrate reserves were associated with a reduction in inflorescences per shoot and flowers per inflorescence in the following season, the reduction as much as 50% compared with non carbohydrate stressed vines. While there were strong linear or curvilinear relationships between the concentration of starch in trunks and roots at bud burst and inflorescences per shoot and flowers per inflorescence, in case the of inflorescences per shoot, there was not an immediate cause and effect because inflorescences were initiated in the previous season. Individual shoot leaf removal during the inflorescence initiation period illustrated that leaf removal directly inhibited the initiation of inflorescences in latent buds. Shoot carbohydrate measurements showed a strong curvilinear relationship to the number of inflorescences per shoot, with a threshold starch concentration of 10-12%Dwt during the inflorescence initiation period required for a maximum number of inflorescences per shoot. Furthermore, examination of individual node positions emphasised the importance of the subtending leaf on the initiation of inflorescences within the latent bud. The number of inflorescences per shoot post bud burst was reduced on vines that were both carbohydrate reserve stressed (by previous season's defoliation) and had a high node (108) number retained per vine after winter pruning compared with little or no reduction in inflorescences per shoot on carbohydrate reserve stressed vines that had a low (20) node number per vine. The reduction in inflorescences per shoot on high node vines was associated with reduced carbohydrate reserves and reduced shoot vigour (thinner and lighter shoots). Flowers per inflorescence were reduced by as much 50% in response to lower overwintering carbohydrate reserves. Fewer flowers per inflorescence were attributed to a reduction in primary branching of the inflorescence and also a reduction in flowers per branch. Strong linear relationships between the concentrations of starch in trunks and roots and flowers per inflorescence indicate that the determination of flowers per inflorescence, unlike inflorescences per shoot, may be dependent on the level of overwintering carbohydrate reserves. This is most likely due to changes in branching of the inflorescence and individual flower formation occurring during the bud burst period. Per cent fruitset was not affected by reductions in carbohydrate reserves, so fewer inflorescences per shoot and flowers per inflorescence resulted in reduced vine yield. The findings of this thesis indicate that changes in the level of carbohydrate production and partitioning in response to a range of viticultural management practices and seasonal weather contribute to seasonal variation in grapevine flowering and yields in New Zealand's cool climate environment. The relationships between carbohydrate reserves and flowering illustrate the potential to use this information to predict grapevine flowering and forecast yields. The practical implications of this research illustrate that the viticulturist must manage grapevines not only for the current crop, but also for subsequent crops by maintaining sufficient carbohydrate reserves for balanced growth flowering and fruiting from season to season.

Cette étude partira de deux principes fondamentaux. D’abord, elle considérera le goût du vin comme une construction complexe qui, par l’exercice de la dégustation, convoque à fois la vue, la capacité à percevoir les saveurs, et la mémoire olfactive. Ensuite, elle concevra le goût comme le rapport esthétique et discriminatoire qu’on peut entretenir avec un objet. En ce sens, l’argumentation aura pour but d’explorer les aspects de la dégustation dans la « large Antiquité », en comparant de manière systématique la littérature grecque à la littérature latine. Comme le vocabulaire pour parler du vin est aussi sensoriel (amer, sucré) qu’extrasensoriel (charpenté, costaud), nous proposerons dans cette étude une relecture des sources pour voir de quelle manière les Anciens caractérisaient le vin qu’ils dégustaient. Le tout, en démontrant comment couleur, harmonie, goûts et textures jouent un rôle dans la compréhension et le développement du goût du vin. La comparaison des sources grecques et latines tentera de montrer qu’un véritable raffinement de vocabulaire est perceptible au courant des Ier et IIe siècles, en lien avec la constitution d’une sphère plus spécialisée de dégustateurs. L’exercice sera donc réalisé sans oublier le nécessaire retour à la terre pour comprendre les principes fondamentaux de la vitiviniculture. L’ensemble, en suggérant que la terminologie relative aux saveurs et les techniques agricoles de l’Antiquité sont capables de capturer des complexités similaires à celles d’aujourd’hui. L’examen des sources aura également pour but de démontrer qu’avec l’enrichissement indéniable de ce vocabulaire, un véritable exercice de distinction sociale se dessine pour l’élite romaine en situation de dégustation. Par la dialectique propre au vin, nous tenterons de voir que de la vigne au chai puis du cellier à la table, la pratique de la dégustation en milieu social inclut et exclut, fonde et déconstruit, honore et ridiculise à la fois. / This study will start from two fundamental principles. Firstly, it will consider the taste of wine as a complex construction which, through the exercise of tasting, convokes at the same time the sight, the ability to perceive flavours, and the olfactory memory. Secondly, it will conceive taste as the aesthetic and discriminatory relationship that one can maintain with an object. To that extent, the argumentation will explore aspects of tasting in the "broad Antiquity" by systematically comparing Greek literature with Latin literature. Because the vocabulary used to talk about wine is as sensory (bitter, sweet) as it is extrasensory (robust, full-bodied), we will propose in this study a new reading of the sources to see how the Ancients characterized the wine they tasted. All of this, while demonstrating how color, harmony, tastes and textures play a role in the understanding and development of the taste of wine. The comparison of Greek and Latin sources will try to show that a real refinement of vocabulary is perceptible during the first and second centuries, in connection with the constitution of a more specialized sphere of tasters. The exercise will therefore be carried out without forgetting the necessary basics of agriculture to understand the fundamental principles of winemaking. Taken together, suggesting that the flavor terminology and agricultural techniques of antiquity are capable of capturing complexities similar to those of today. The examination of the sources will also aim to demonstrate that with the undeniable enrichment of this vocabulary, a real exercise in social distinction for the Roman elite in tasting situations is taking shape. Through a dialectic specific to wine, we will try to see that from the vine to the cellar and then from the cellar to the table, the practice of tasting in a social environment both includes and excludes, builds and deconstructs, honors and mocks.

Terroir is determined by a combination of factors in the vineyard including the grape varietal, geology and soil, soil hydrology, physiography, and climate. Although most studies have examined regional differences in wine flavors and associated provenance of wine based on chemistry, few have examined the chemistry of the soil and the ability to trace that chemistry to grape juice and, finally, to the wine. This dissertation examines what soil physical and chemical differences specific to this region might influence grape juice chemistry and wine chemistry. Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic, marine sediments, and loess/volcanic. Winemakers have observed differences in the flavor of Pinot Noir wine made from grapes grown on these different parent materials. This dissertation examines differences in the soil properties and elemental chemistry of the soil parent materials at various vineyards to document their effect on wine chemistry as a step towards understanding differences in flavor. All aspects of the terroir are controlled by carefully selecting vineyards with similar exposure and elevation, the same grape varietal and wine making techniques, and only the soils vary. The hypothesis is that the chemistry of the grape juice and wine reflect the soil in which the grapes were grown and that the three parent materials have soils that can be distinguished by their physical and chemical characteristics. Soil pits were excavated in 20 vineyards, soil properties were described in the field, and soil samples were later analyzed in the laboratory particle size, organic matter, color, pH, cation exchange capacity (ammonium acetate method), clay mineralogy (x-ray diffraction), and elemental chemistry (ICP-MS/AES). X-ray fluorescence was used to examine the pisolites. ICP-MS/AES was used for elemental analysis of grape juice and wines produced from these vineyards. Principal component analysis was used to compare soil physical and chemical characteristics, grape juice and wine chemistry. The physical characteristics of soils from all the three parent materials indicate: they are old (>50,000 years) based on their high clay content, low cation exchange capacity, red colors, and high Fe and Al content. These features indicate enough time has passed to reduce organic matter and other cations at depth, leave behind insoluble Fe and Al, and develop pedogenic clays. In my study region, volcanic and marine sediment soils are more developed with slightly lower acidity than the loess/volcanic soils. A new finding for this region is the presence of pisolites (Fe/Mg concretions) in the volcanic and the loess/volcanic soils, but absent in the marine sediment soils. Winemakers hypothesized that pisolites were present only in loess soils and influenced wine flavor in some way. Volcanic soils have the highest P, S, Fe, Co, Mn, and V concentrations and the lowest As and Sr values. Marine sediment soils have higher Cl and Sr and lower P, Co, Mn, Ba, and V concentrations than volcanic soils. Loess soils have the highest values of K and Mg and are similar to volcanic soils with higher P and V values and similar to marine sediment soils with higher Sr values. The main elements found to be significant in determining one parent material from another are V and Mn (volcanic soils), Mg and K (loess soils), and Sr (marine sediment or loess soils). Sr is slightly higher in grape juice and wine from vines grown on marine sediment parent material compared to volcanic and loess parent material, whereas Mn is higher in the juice and wine from grapes grown in volcanic parent material. P, S, Fe, Co, V, Cl, Ba, Mg, and K did not maintain their relative concentration levels from soil to grape juice to wine. The principal component analysis shows that soil and wine chemistry differs between parent material, but is inconclusive for grape juice chemistry.

The influence of rootstock and canopy density on grape berry composition was investigated over the summer of 2003-2004 on a commercial vineyard at Waipara, North Canterbury. This experiment was designed to investigate the influence of rootstock and canopy density on the acid composition, potassium (K) content and final pH of harvested fruit (Pinot Noir AM 10/5 Lincoln Selection). The trial block consisted of eight rootstocks laid out to an 8 x 8 latin square, each plot consisting of five vines of the same rootstock. Two canopy treatments were overlaid the block (down whole rows, assigned randomly, four rows to each treatment); one treatment allowed to grow naturally, in the other treatment the canopy was thinned removing double burst shoots and laterals. The bunch numbers were adjusted in the Unthinned canopy treatment (UCT) to match the Thinned canopy treatment (TCT). Information was gathered to assess: the canopy size and density (Pinot Quadrat Leaf Layer and Percent Gaps and canopy porosity), the plant yield (and berry size, berries per cluster, cluster weight, clusters per plant), plant K levels at flowering and veraison (from petioles and leaf blades) and berry composition at harvest (soluble solids (as brix), K, titratable acidity (TA), tartaric acid concentration, malic acid concentration and pH). The trial area was non-irrigated on clay loam soils and viticultural management was to best commercial practice. It was found that although rootstock influenced the levels of K in the plant and in the juice at harvest, the level of K in the juice did not influence pH in this experiment (range of rootstock juice K: 808 ppm to 928 ppm, l.s.d. = 75 ppm). The level of tartaric acid concentration in the juice was found to be the dominant influence on the level of pH in this experiment (rootstock pH range: 3.21 to 3.39, l.s.d. = 0.05). The juice concentration of tartaric acid was influenced by both rootstock (rootstock range 4.0 to 4.7 g/L, l.s.d = 0.4) and canopy density (UCT = 4.1, TCT = 4.7, l.s.d. = 0.4), decreased shading positively increasing the level of tartaric acid. The malic acid concentration in the juice was positively influenced by increasing canopy density (UCT = 4.7 g/L, TCT = 4.1 g/L, l.s.d = 0.4) and this played a minor role in the determination of pH in this experiment; an influence of rootstock on the level of malic acid concentration was found. The malic acid concentration strongly influenced the determination of TA (UCT = 11.0 g/L, TCT = 10.2 g/L, l.s.d = 0.5); tartaric acid concentration had a minor influence on the recorded TA. Attempts to characterise the influence of rootstock on malic acid, tartaric acid and pH were inconclusive. Rootstock was found to influence the canopy variables measured in this experiment and the recorded average plant yield. Crosses of Vitis rupestris were found to exhibit the most canopy vigour and those derived from Vitis berlandieri and Vitis riparia the least. The Canopy treatment did not show an influence over yield but the rootstock was found to influence plant yield, through the numbers of berries set in a cluster and the final harvest cluster weight. The influence of rootstock on pH may be described by the influence it exerts on canopy growth and yield but this was thought unlikely. Further research is required to describe the nature of the rootstock influence on K, malic acid, tartaric acid and pH.

The effects of crop load and berry exposure on the composition of Marlborough Sauvignon blanc grapes and wine from the Brancott vineyard, Blenheim, were explored. Commercially grown, 2-cane and 4-cane Sauvignon blanc vines were used with a row orientation of north-south. Two exposure treatments were imposed in the following manner: complete leaf removal was undertaken in the fruit zone and 50% shade cloth was erected to give a uniform shading treatment to half the trial vines. Weekly thirty-berry and whole bunch samples were taken from each of the 32 plots with the exception of the veraison period when two samples per week were taken. Vine vigour was assessed using pruning and leaf area per vine data. Harvest occurred on different dates for 2-cane and 4-cane pruned vines so that fruit attained from both treatments had similar °Brix. Fruit was processed at the Lincoln University winery. Must analysis and wine analysis were undertaken. As expected, 4-cane vines had almost double the yield of 2-cane vines. Higher crop load significantly reduced leaf area per shoot and shoot thickness. Lower leaf area to fruit ratio for 4-cane berries resulted in delayed onset of veraison and slowed the rate of sugar accumulation. Crop load, which limited leaf area to fruit ratio, appeared to be the dominant factor in determining timing of grape physiological ripeness as expressed by °Brix over other factors such as fruit exposure. Malic acid, tartaric acid, IPMP (iso-propylmethoxypyrazine) and IBMP (iso-butyl-methoxypyrazine) were lower at equivalent °Brix in 4-cane compared with 2-cane berries. Significantly higher concentrations of quercetin were found in exposed compared to shaded berries. Must analysis showed a significant influence of crop load on berry titratable acidity and pH, reflecting berry ripening results. Exposure significantly increased the concentrations of nitrogenous compounds in 4-cane must yet showed no influence on 2-cane must. After wine processing lower malic acid concentrations in wines made from 100% exposed fruit became evident in lower wine titratable acidity but showed no influence on wine pH. Bentonite addition to wines had a small but statistically significant influence on wine by reducing pH, titratable acidity and alcohol. Bound sulphur concentrations were significantly higher in 4-cane versus 2-cane wines. At harvest, methoxypyrazine levels in grapes and wines were very low; IBMP concentrations where significantly lower than those normally found in Sauvignon blanc wines from Marlborough. This was attributed to the absence of basal leaves from the shoots of ripening berries. The results suggest that leaf area to fruit ratio is a powerful determinant of grape and wine quality.