Compositional changes of skin and seed phenolic compounds and berry glycosylated aroma precursors were measured in Vitis vinifera L. cv. Cabernet Sauvignon onto 1103P and SO4 rootstocks, in three irrigation regimes (FI, 100% of evapotranspiration; DI, 50% of evapotranspiration; and NI, non-irrigated). The study was conducted in a commercial vineyard of central Greece, in a factorial experiment during two growing seasons (2005-2006). Grape samples were obtained at commercial harvest. The deficit water supply decreased berry size but did not affect the skin/pulp weight ratio. Water limitation, especially pre-veraison, caused a substantial increase of skin anthocyanin concentration, and this effect was independent of water deficit-induced reductions in berry size and vine vigor. Among individual anthocyanins, malvidin-3-O-glucoside was mostly affected by water supply. The rootstock genotype did not affect berry growth parameters and skin polyphenol concentrations. The irrigation regime (mainly post-veraison) and rootstock genotype affected total flavan-3-ol monomers in seed tissue, mainly as a result of variations in the catechin amount. The lower seed phenolic concentration was found in non-irrigated and SO4-grafted vines, probably as a result of the restriction of scion vigor caused by these treatments, thereby altering cluster exposure. Skin and seed tannins were not affected by either rootstock or irrigation. The limited water supply was associated with increased aroma potential at harvest.
Effects of nitrogen (M) and water supply on grapevine leaf transmittance and canopy reflectance were studied over 2 years (2009)(2010) in two vineyards planted with cvs. Cabernet Sauvignon and Xinomavro (Vitis vinifera L.) located in northern Greece. Three N (0, 60 and 120 kg ha -1 ) and two irrigation (irrigated at 70 % of crop evapotranspiration and non-irrigated) treatments were managed in triplicate in randomized blocks. Measurements with two transmittance-based chlorophyll meters (CM: SPAD-502 and CCM-200) and two active canopy sensors (Crop Circle ACS-210; amber band and Crop Circle ACS-430; red and red edge bands) were conducted on four and two growth stages, respectively. Fertilization increased leaf N and chlorophyll concentrations, as well as CM readings and vegetation indices. The CCM and SPAD values did not vary across growth stages and better estimated leaf N and chlorophyll concentrations in Cabernet Sauvignon than in Xinomavro. The SPAD readings provided better predictions of leaf N concentration. The vegetation indices of the ACS-430 sensor correlated with leaf N and chlorophyll concentrations and dormant wood in Cabernet Sauvignon; the red edge-based indices were generally more efficient than the red-based indices. Consistent relationships were observed for all ACS-430 indices with yield and for red edge-based indices with total phenols early in the season for both vineyards. The correlation between ACS-210 sensor indices and vine properties was low. These results showed that the two technologies examined could provide information on grapevine performance early in the season but have limitations that may restrict their use in vineyards because the acquired relationships were not consistent across vineyards and instruments.
For two growing seasons (2005 and 2006), leaves of grapevine cv. Cabernet-Sauvignon were collected at three growth stages (bunch closure, veraison, and ripeness) from 10-year-old vines grafted on 1103 Paulsen and SO4 rootstocks and subjected to three watering regimes in a commercial vineyard in central Greece. Leaf shape parameters (leaf area − LA, perimeter − Per, maximum midvein length − L, maximum width − W, and average radial − AR) were determined using an image analysis system. Leaf morphology was affected by sampling time but not by year, rootstock, or irrigation treatment. The rootstock×irrigation×sampling time interaction was significant for all the leaf shape parameters (LA, Per, L, W, and AR) and the means of the interaction were used to establish relationships between them. A highly significant linear function between L and LA could be used as a non-destructive LA prediction model for Cabernet-Sauvignon. Eleven models proposed for the non-destructive LA estimation in various grapevine cultivars were evaluated for their accuracy in predicting LA in this cultivar. For all the models, highly significant linear functions were found between calculated and measured LA. Based on r 2 and the mean square deviation (MSD), the model proposed for LA estimation in cv. Cencibel [LA = 0.587(L×W)] was the most appropriate.Additional key words: leaf length; leaf width; non-destructive methods; Vitis vinifera.
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