Academic literature on the topic 'Xynisteri'

The world’s changing climate is placing great pressure on the resources for sustainable viticulture. With this, it has become necessary to investigate grape varieties that are well adapted to hot climates. This study investigated whether two Cypriot varieties (Xynisteri and Maratheftiko) responded differently to Shiraz and Sauvignon Blanc grown under different irrigation regimes (full, 50% and 25%). Irrigation trials were established in Cyprus in 2019 and in Australia in 2020/2021. Vine growth and physiology and fruit composition (field trial only) measurements were recorded. The trial in Cyprus in 2019 demonstrated that for all three irrigation regimes, Xynisteri had higher stem water potential, stomatal conductance, chlorophyll and greater biomass than Sauvignon Blanc under all irrigation regimes. In 2020/2021, Xynisteri had a greater biomass than Maratheftiko and Sauvignon Blanc, with Shiraz having the lowest. Under reduced irrigation, Xynisteri and Maratheftiko had higher stem water potential, stomatal conductance and chlorophyll content than Shiraz and Sauvignon Blanc. These results indicate that Xynisteri in particular may possess better cultivar-specific growth traits than Shiraz and Sauvignon Blanc when grown under the same environmental conditions and in turn may be a more appropriate choice in areas where water is limited.

The impact of climate change on viticulture is of major importance. Several international and indigenous grapevine cultivars have been examined for their adaptive performance to drought and heat stresses. However, the underlying physiological mechanisms are not well known. In the present study we examined the short-term effects of light and moderate drought stress (DS) as well as heat stress (HS) on physiological and biochemical attributes in two grapevine cultivars: Chardonnay (international) and Xynisteri, an indigenous adapted to the specific Cypriot microclimate. Xynisteri plants exhibited decreasing leaf stomatal conductance and photosynthetic rate as well as increasing total phenols and antioxidant capacity under DS conditions. These reactions were concomitant to a rapid accumulation of hydrogen peroxide and lipid peroxidation in leaves, associated to an increase of the antioxidant superoxide dismutase activity. However, Chardonnay plants did not exhibit the same responses as Xynisteri against DS (i.e., stomatal closure, total phenolics and antioxidants) over the first four days. Additionally, Chardonnay showed leaf damage with increased lipid peroxidation levels and activation of catalase and peroxidase. Interestingly, HS increased leaf stomatal conductance and decreased total phenolic content, flavonoids and antioxidant capacity in Chardonnay after 20 d of stress. In both cultivars, HS had milder effects compared to DS, and again Xynisteri showed better performance than Chardonnay in terms of damage index and antioxidative activities. Overall, Xynisteri adaptation to DS and HS was higher than that of Chardonnay, and both cultivars reacted more to the short-term DS than to HS. Although the Xynisteri performances under stress conditions provide an important resource for adaptation to stressful conditions, the impacts on earliness, yield and grape quality remain to be explored.

Cyprus has a long tradition in grape cultivation and wine making and grapevine is important for the sustainability of the agricultural sector, like in other Mediterranean areas. Water scarcity, which is projected to increase due to climate change, could negatively affect the sector. In this research, the effects of irrigation and tillage treatments on various aspects of vine growth and product quality (e.g., yield, physiology and quality attributes), were studied in Chardonnay and Xynisteri cultivars grown in clay soils in Cyprus. Regarding soil properties and water content, N and K were more abundant in the soil than P and through the growing period irrigation tended to increase electrical conductivity (EC) in the soil. Soil water content (volumetric) was 22%–27.5% and 13%–16%, when irrigation was applied or not, respectively. Vegetative soil cover occupied 50%–55% of the surface and contained species typically present in Mediterranean farms (e.g., Poaceae, Fabaceae and Brassicaceae). Tillage increased yield in Xynisteri (4–5 kg plant−1) but negatively affected other parameters such as chlorophyll levels (in Xynisteri). In combination with irrigation, tillage increased antioxidant activity in Chardonnay (assessed by FRAP and DPPH), at harvest. Total phenolics at harvest were higher in the grape juice of Xynisteri, compared to Chardonnay (30–40 and 20–25 mg GA g−1 fresh weight, respectively). Irrigation influenced phytohormone levels in the two cultivars. ABA increased in non-irrigated Xynisteri, reflecting an increased capacity to react towards water stress. Water stress is considered to increase polyphenols in grapes, but in the case of Xynisteri it seems that irrigation water is required to obtain better quality grapes as without irrigation volumetric water content (VWC) is close to the permanent wilting point. Titratable acidity and total tannins decreased in Chardonnay, when tillage and irrigation were applied. In addition, tillage and irrigation tended to elevate the pH of the grape juice. Tillage and irrigation on the other hand, had no effect on the levels of ascorbic acid and total anthocyanin content. The results of this research may help to select management strategies that support the adaptation of viticulture to climate change in Cyprus and other Mediterranean areas.

Aim: The aims of this study were to (1) formulate a baseline understanding of the performance of the indigenous Cypriot white grape Xynisteri and the red grape Maratheftiko (Vitis vinifera L.), and (2) compare these varieties to Shiraz and Sauvignon blanc grown in a Cypriot vineyard.Materials and results: The investigation involved multiple dry grown vineyards from the Krasochoria region of Lemesos, Cyprus, during the 2017, 2018 and 2019 vintages. Vine performance measurements, including midday stem water potential, stomatal conductance, chlorophyll content, stomata density, vine phenology and vegetative and reproductive measurements, were taken at flowering, veraison and pre-harvest. Xynisteri had the greatest stomatal density, more shoots, more leaves, heavier bunches, greater yield, higher leaf water potential at harvest, and a stomatal conductance equal to Maratheftiko, but greater than that of both Shiraz and Sauvignon blanc. Maratheftiko had the longest shoots, largest shoot diameter and the greatest chlorophyll content out of all four varieties.Conclusions: This study identified the ability of the indigenous Cypriot grape varieties, Xynisteri and Maratheftiko, to better tolerate hot and dry conditions when compared to more commonly cultivated varieties grown in the same environmental conditions.Significance and impact of the study: The changing climate of wine growing regions worldwide is placing great pressure on the resources for sustainable viticulture. Many vineyards in hot climate zones base their businesses on European grape varieties traditionally grown in regions with abundant water resources. It is therefore necessary for the global wine industry to investigate grape varieties that are indigenous to hot climates. The eastern Mediterranean island of Cyprus is one such place, with more than 10 indigenous grape varieties that grow well in a hot climate without irrigation. Consumer studies have demonstrated that wines made from these Cypriot varieties are equally, if not more, acceptable than wines made from more traditional European grapes; therefore, the potential for their use in other hot wine growing regions is promising.

Climate change will increase the occurrence of plants being simultaneously subjected to drought and pathogen stress. Drought can alter the way in which plants respond to pathogens. This research addresses how grapevine responds to the concurrent challenge of drought stress and Plasmopara viticola, the causal agent of downy mildew, and how one stress affects the other. Self-rooted cuttings of the drought-tolerant grapevine cultivar Xynisteri and the drought-sensitive cultivar Chardonnay were exposed to full or deficit irrigation (40% of full irrigation) and artificially inoculated with P. viticola in vitro or in planta. Leaves were sampled at an early infection stage to determine the influence of the single and combined stresses on oxidative parameters, chlorophyll, and phytohormones. Under full irrigation, Xynisteri was more susceptible to P. viticola than the drought-sensitive cultivar Chardonnay. Drought stress increased the susceptibility of grapevine leaves inoculated in vitro, but both cultivars showed resistance against P. viticola when inoculated in planta. Abscisic acid, rather than jasmonic acid and salicylic acid, seemed to play a prominent role in this resistance. The irrigation-dependent susceptibility observed in this study indicates that the practices used to mitigate the effects of climate change may have a profound impact on plant pathogens.

Polyfunctional thiols have previously been shown to be key aroma compounds in Sauvignon blanc and more recently in Chardonnay wines. Their role in other wine varieties such as those made from three popular indigenous Cypriot grape varieties has remained unexplored. As an extension of a previous project that profiled the sensory and chemical characteristics of Cypriot wines and their comparison to Australian wines, this study aimed to investigate five potent thiols in Xynisteri, Maratheftiko, Giannoudhi, Pinot gris, Chardonnay and Shiraz wines. Wines were analysed utilising Stable Isotope Dilution Assay (SIDA) with derivatisation and High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC-MS/MS). The varietal thiols measured were 4-methyl-4-sulfanylpentan-2-one (4MSP) that has an aroma of “boxwood” and “cat urine” at high concentration, 3-sulfanylhexan-1-ol (3SH) which has been described as having a “grapefruit/tropical fruit” aroma, and 3-sulfanylhexyl acetate (3SHA) that has also been described as having an aroma of “passionfruit”. Additionally, two other potent thiols were measured including benzyl mercaptan (BM) that has an aroma of “smoke and meat” and furfuryl thiol (FFT) that has been described as having a “roasted coffee” like aroma. The reason these thiols are known as potent thiols are due to their very low aroma detection thresholds in the low ng/L (ppt) range. Of the thiols that were measured, 3SH was the only varietal thiol detected in the red wine samples. All of the white wine samples contained 3SH, BM and 3SHA, whereas 4MSP was only detected in Pinot gris and three Xynisteri wines. The potent thiol, FFT, was detected only in the Chardonnay and four of the Xynisteri wines. Interestingly the thiols that were present in the samples were found at concentrations above their aroma detection thresholds (determined in hydroalcoholic solutions), especially 3SH which was found in an order of magnitude above its aroma detection threshold. These findings provide early knowledge of the presence of these thiols in Cypriot wines, compared with Australian wines and establish any relationships between this chemical data with previous wine sensory profile data.

The current work evaluated spray coverage and pest control effectiveness against the grape berry moth (Lobesia botrana) by two different spray technologies and volume rates: A spray gun (high-volume sprayer—HVS) calibrated at 1000 L ha−1 and a conventional orchard sprayer calibrated at 500 L ha−1 (OS500) or 250 L ha−1 (OS250). Experiments were carried out in three different grape varieties over two years in mountain vineyards on the Mediterranean island of Cyprus. The median coverage for HVS remained above 80% for all three varieties, while that for OS500 ranged from 26% to 56%, and that for OS250 from 18% to 37%. Infestation by the grape berry moth varied from about 2.5% for Palomino, to 8% for Carignan and 3.2% for Xynisteri. Infestation in sprayed plots remained below 1.8% for all treatments, varieties and study years. Although infestation levels in OS250 were not different than the control in two varieties, the infestation levels among sprayer treatments did not differ by more than one percentage point. The current work suggests that lowering application volume and pesticide amount to 50% or more, in some cases, provides adequate control and represents an effective option for reducing pesticide use in vineyards.

Cypriot vineyards are considered as one among the earliest niches of viticulture and a pivotal hub for the domestication and dissemination of grapevine. The millennial presence of Vitis spp. in this Eastern Mediterranean island has given rise to a plethora of biotypes that have not been adequately characterized, despite their unique attributes and stress tolerance. This ancient germplasm also has an additional value since it survived the phylloxera outbreak; hence, it possesses a large amount of genetic diversity that has been unnoticed. In order to provide useful insights to the lineage of Cypriot vineyards, a two-year-spanning collection of centennial grapevine cultivars mostly regarded to belong to four indigenous variety clusters (“Mavro”, “Xynisteri”, “Maratheftiko”, and “Veriko”) was initiated. There were 164 accessions across the broader Commandaria wine zone sampled and characterized using a universal microsatellite primer set. Genetic analysis indicated that considered indigenous Cypriot germplasm has a polyclonal structure with a high level of heterozygosity. Moreover, several lineages or unexplored varieties may exist, since a larger than considered number of discrete genotypes was discovered. Furthermore, it was established that grapevine lineages in Cyprus were shaped across eras via clonal, as well as, sexual propagation. The special attributes of the Cypriot landscape are discussed.

International agreements and policies on climate change urge for a drastic reduction in greenhouse gas (GHG) emissions to prevent a temperature rise above 2 °C at the end of the century. Determination of the product carbon footprint (CF), identifying carbon hotspots and examining ways for CF reduction is an essential step towards mitigation actions. Viticulture and winemaking are very important for the economy of Mediterranean regions, especially for the sustainability of rural areas. To determine the CF for wine, the Life Cycle Assessment (LCA) approach was adopted with system boundaries from vineyard to market. Input data were collected from 20 vineyards on the island of Cyprus, where the indigenous Xynisteri variety is cultivated and from an SME winery that uses the grapes to produce wine. The winery CF was 99,586 kg CO2-eq for 76,000 bottles produced (1.31 kg/0.75 L bottle). The uncertainty factor was determined to be ±50%, which was considered adequate for the methodology followed. The share of electrical energy was 46%, of packaging 18% and of the vineyard 16%. Fuel (transportation and heating), as well as waste management (solid and wastewater) contributed 10% each to the CF. There is potential for mitigation of the CF by replacing the bottles currently used by lighter ones, lowering the energy use and reusing a part of the solid waste as fertilizer. Research towards eco-innovation of viticulture/winemaking is essential for reducing the footprint of the sector to promote sustainable wine production.

The threat of climate change to the global wine industry is well documented. As such, many wine regions of the world are expected to face significant impacts in the next 50 years encompassing increasing temperatures, reduced rainfall, earlier harvests and heat induced berry composition changes. The majority of vineyards and wineries base their businesses on European grape varieties that traditionally do not have problems with water resources. This has led countries to investigate options to adapt to these challenges, with a particular focus on the drought and heat tolerant indigenous grape varieties of hot Mediterranean climates. Recently in Australia, producers have been seeking potential drought tolerant varieties from Greece, Portugal, Spain and Georgia. However, very little research has assessed these varieties under Australian conditions and there is a lack of knowledge on how they perform. The island of Cyprus is another hot wine growing region with a recent upsurge in interest and research into heat and drought tolerance and a return to cultivation of their indigenous varieties. To date there are at least 12 indigenous varieties that have been identified in Cyprus, but recent research indicates there could be more varieties and numerous clones in their germplasm. The aims of this project were to investigate the potential of two indigenous grape varieties from Cyprus for use in Australian viticulture and oenology. They objectives to meet these aims included: (1) generate sensory and chemical profiles of commercial Cypriot wines made from the white grape Xynisteri and the red grapes Maratheftiko and Giannoudhi compared to Australian Shiraz, Pinot Gris and Chardonnay wines, (2) assess the Australian consumers’ response to these wines, (3) investigate five potent thiols in Xynisteri, Maratheftiko, Giannoudhi, Pinot Gris, Chardonnay and Shiraz wines, (4) formulate a baseline understanding of the performance of the indigenous Cypriot white grape Xynisteri and the red grape Maratheftiko (Vitis vinifera L.), (5) compare these varieties to Shiraz and Sauvignon Blanc grown in a Cypriot vineyard, (6) assess the response of Xynisteri to different irrigation regimes and (7) compare the performance of Xynisteri, Maratheftiko, Shiraz and Sauvignon Blanc grown in pots with different irrigation regimes in Australia and Cyprus. This research has addressed the seven aims by providing new knowledge on several aspects of Xynisteri and Maratheftiko grapevines and their wines. They include, the chemical composition and sensory attributes of wines made from these varieties. Consumers have demonstrated a liking for the wines and in some cases preferred these wines to wine made from more common varieties. Xynisteri was described sensorially as citrus, herbaceous, dried fruit, savoury, apple, pear, grass, herbaceous with a full length of fruit and non-fruit flavours in the after taste. Maratheftiko was described sensorially as dried fruit, strawberry, cherry, jammy, confectionery, bitter, sweet, chocolate, herbaceous and with full length of fruit flavours in the after taste. For the first time, chemical analysis supported this sensory analysis with aroma compounds correlating to chemical compounds responsible for these aromas and tastes. Varietal thiols are important compounds in certain varieties when fruity, tropical and citrus aromas are desired. This study measured the concentration of varietal thiols in these Cypriot wines and the concentration determined in these wines was comparable to those found in popular Australian wines such as Chardonnay and Sauvignon Blanc. Xynisteri and Maratheftiko growing in non-irrigated vineyards in Cyprus were bench marked against more commonly grown varieties for the first time. Along with this, irrigation trials in Australia and Cyprus compared the vine growth response to different irrigation regimes and highlighted that the Cypriot varieties were better suited to heat and drought stress than more commonly grown varieties due to their stomatal density and stomatal conductance assisting in managing midday stem water potential under heat and drought stress. Xynisteri in particular, was able to produce large above and below ground biomass under all irrigation conditions. Maratheftiko achieved large above ground biomass also but less below ground biomass than Xynisteri. However, both Xynisteri and Maratheftiko had total biomass greater than Shiraz and Sauvignon Blanc. This research has identified several aspects of the Cypriot varieties Xynisteri and Maratheftiko that may make them suitable for cultivation in Australia. Consumer trials indicated acceptance of wines made from these varieties, highlighting potential marketing opportunities to target markets. It has also provided information that will guide future research in terms of how these varieties perform in Australian commercial vineyards and the mechanisms by which they achieve their drought resilience.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2021