The effect of progressive drought on water relations and photosynthetic performance of two grapevine cultivars (Vitis vinifera L.)

Preliminary measurements were carried out in order to asses the effect of water deficit on photosynthesis and water relations of two grapevine cultivars (Vitis vinifera L. cv. Kékfrankos and Vitis vinifera L. cv. Portugieser grafted on 5BB rootstock) tolerance and sensitive to drought, respectively. Three treatments were applied on both cultivars such as 100%, 50% and 30% field capacity under glasshouse conditions. Pre-dawn water potential and gas-exchange parameters (assimilation rate, transpiration, stomatal conductance) were consistently lower in drought stressed plants indicating moderate water stress at 50% field capacity and severe water deficit at 30% field capacity. Midday water potential indicated “close to isohydric” characteristic of both cultivars. Moderate water deficit resulted in an increase in water-use efficiency (WUE). However, Kékfrankos had a significantly higher WUE than Portugieser

Bud cold-hardiness of some Vitis vinifera L. cultivars during the dormant season of 2018/2019

Kutatásunk során négy borszőlőfajta téli rügyeinek fagytűrő-képességét vizsgáltuk (Kékfrankos, Ménesi Kadarka, Merlot, és Syrah). A mintákat a Kőlyuktető dűlőből (Eszterházy Károly Egyetem Szőlőbirtok) gyűjtöttük közvetlenül a mérések előtt. A vizsgálat 2018 decemberétől 2019. március végéig tartott. Méréseinket egy differenciális hőelemzésre alkalmas eszközzel (DTA) végeztük, felhasználva a növényi sejten kívüli és sejten belüli víz megfagyásakor történő látens hő képződését. Eredményeink alapján a téli időszakban a Kékfrankos bizonyult a leginkább ellenállóbbnak, majd a Ménesi Kadarka, Syrah és Merlot. A rügyfakadáshoz közeledve a Ménesi Kadarka fagytűrő-képessége a többi fajtához képest nagyobb mértékű csökkenést mutatott. ----- In our research we examined the bud cold-hardiness of four Vitis vinifera L. cultivars (Lemberger, Cadarca de Minis, Merlot and Syrah). The samples were collected from vines growing outdoors in the Kőlyuktető vineyard (Eszterházy Károly University). The work was conducted between December 2018 and March 2019. A Differential Thermal Analyser had been used to define the low temperature exotherms during the intracellular fluid freezing. According to our results, Lemberger showed the highest hardiness among all tested cultivars, followed by Cadarca de Minis, Syrah and Merlot. Cadarca de Minis appeared to lose hardiness more rapidly in spring, indicating it could be sensitive to spring frosts

Pressure-volume analysis of two grapevine cultivars ('Kékfrankos' and 'Portugieser', Vitis vinifera L.): water deficit, osmotic conditions and their possible relations with drought tolerance

Two grapevine cultivars, 'Kékfrankos'and 'Portugieser' rafted onto Teleki-Kober 5BB were investigated during regulated deficit irrigation under greenhouse conditions. Four-year old grapevine plants in 50 L white plastic containers were examined using perlite (20 %), loamy soil (30 %) and peat (50 %) (v/v) mixtureas a substrate. Two treatments were applied: 100 % (nonstressed)and 50 % (moderately stressed) field capacity.'Kékfrankos' has a stronger tolerance against water deficit compared to 'Portugieser' on tissue level. This characteristic is mainly due to the osmotic relations and the elastic tissue properties of this variety. Higher osmotic concentration resulted in delayed turgor loss point,and thus longer cell integrity

Water relations and photosynthetic responses of Kékfrankos grapevine (Vitis vinifera L.) in two terroirs with different ecological conditions

Behaviour of Kékfrankos (Vitis vinifera L.) grapevine in two terroirs (Eger-Nagyeged–hill and Eger-Kőlyuktető) were examined during the growing season 2003. There was a close relationship between physiological responses, yield, fruit quality and terroir environmental conditions. Lower water supply in Eger-Nagyeged-hill was detected during the season due to its sloping exposure and soil characteristics. Pressure-volume curves (PV-curves) indicated that there was no osmotic adjustment in the leaves of this variety. Higher osmotic concentration was measured in the leaves of the unstressed terroirs presumably due to higher photosynthetic activity. Differences in soil water content of the 2 terroirs resulted in altered cell wall elasticity of the Kékfrankos variety. Photosynthetic production per unit leaf area and total canopy surface was also affected by available soil water content being lower in Eger-Nagyeged-hill. Physiological distinction of the vines in the 2 terroirs resulted in altered yield and wine quality. Lower yield in Eger-Nagyeged-hill is partly connected to decreased photosynthetic production of the canopy. Improved wine quality of Eger-Nagyeged-hill is due to moderate water stress having positive effect at the end of the growing season and other microclimatic factors, i.e. elevated soil temperature and better sun exposure of leaves and clusters

Texture properties and phenol extractability indices of the grape berry under pre- and post-veraison water deficit (Vitis vinifera L. 'Kékfrankos')

Optimal water supply is one of the most important factors in quality wine making. However, water availability is limited in several wine regions and water shortage is getting even worse due to climate change, especially under arid climate conditions. Therefore, proper water management of the vineyards, the amount and the timing of irrigation will play a crucial role in sustainable viticulture in the near future. In this study, the effect of timing of moderate water deficit on berry texture characteristics and phenolic maturity were investigated. 'Kékfrankos' grapevines were submitted to different water regimes: moderate water deficit from berry set until veraison (WD1), moderate water deficit from veraison until harvest (WD2), no water deficit (C). Concentration of the phenolic components of the grape berry skins and berry mixture for the Glories indices were measured by spectrophotometer (UVmini-1240 CE UV-VIS, Shimadzu, Japan). Cell and seed maturity indices (CMI%, SMI%) were also calculated. Berry texture characteristics were monitored by a TA.XT Plus Texture Analyser (Stable Micro System, UK). Berry skin and seed texture properties were affected by water regimes. Skin and seed hardness of WD1 were significantly lower than those of WD2. Significant differences were found in berry hardness between the treatments (C>WD1>WD2). Berry gumminess, resilience and chewiness of WD2 were lower compared to C and WD1. Anthocyanin extractability was higher when plants were not subjected to post-veraison water limitations (WD1). Furthermore, the seed maturity index was lower when water deficit occurred between berry set and veraison. Pre-veraison water deficit resulted in delayed ripening, softer seeds and thus higher phenol extractability compared to WD2 and C. Late seasonal water deficit resulted in thicker skins, which was accompanied by lower anthocyanin extractability than in WD1 and C. It seems that anthocyanin extractability is influenced by the actual water status of the grapevine rather than skin textural properties. However, there are some connections between skin texture parameters and maturity indices

Combined effect of berry size and postveraison water deficit on grape phenolic maturity and berry texture characteristics (Vitis vinifera L. cv. Portugieser)

The effect of berry size and moderate water deficit on skin phenolic maturity and berry texture behaviour was studied on Portugieser variety (Vitis vinifera L.) under green house conditions. In all berry weight categories (I: 2,01 g) water deficit resulted in reduced sugar concentration due to decreased photosynthetic activity. Interestingly, lower phenolic concentration for unit skin mass was measured in the drought stressed treatment compared to the control, irrespective of berry size. However, the concentration of the phenolic components for one berry was lower in the well watered treatment. This phenomenon was due to the increased skin/flesh ratio of the water stressed vines. Berry skin hardness was probably in connection with its phenolic concentration for unit skin weight. Changes in several berry texture parameters were accompanied by changes in berry size. Berry hardness and skin elasticity increased with berry size in both treatments. On the other hand, skin break force, skin break energy, skin thickness showed increase/decrease only in the case of the stressed vines. This result suggests that texture properties of the water-stressed berries depend on berry size to a greater extent compared to the berries of the non-stressed vines. This phenomenon may be explained by the faster ripening of the smaller and of the water stressed berries

Effects of paraffine oil on leaf and berry mycobiota on two grape varieties

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