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Aim: Root hydraulic conductivity is one of the main factors that control water flow in the soil-plant system and ultimately affect crop irrigation requirements. This work sets out to estimate root water conductivity for three self-rooted or grafted table grape cultivars.Methods and results: We evaluated root water conductivity of the cultivars ‘Black Magic’, ‘Matilde’ and ‘Victoria’ grafted onto 1103 Paulsen rootstock or self-rooted. Measurements were performed on two-year-old table grapes grown in pots filled with pumice. Root water conductivity was determined by placing the pots in a pressure chamber and increasing pressures from 0.05 to 0.30 MPa, at intervals of 0.05 MPa. Plant growth in terms of shoot and root dry matter was also evaluated, as well as leaf and root area.Conclusion: Root water conductivity differed according to cultivar and grafting. The ‘Victoria’ cultivar had higher root water conductivity than the other two, which differed little between them. The grafted plants showed higher root water conductivity than the self-rooted plants, except the plants of the cultivar ‘Matilde’, whose root water conductivity for the grafted and self-rooted plants was almost the same. It was also observed that the higher root water conductivity in relation to cultivar and grafting changed with increasing water flux and was constant for high water flux.Significance and impact of the study: Estimation of root hydraulic conductivity helps to determine the water consumption of the cultivars investigated, whether self-rooted or grafted, as well as the amount of irrigation water to apply to vineyards.

In the last decade, high-density olive planting systems have been developed to facilitate less costly mechanical harvesting and pruning by using straddle harvesters. High-density orchards allow faster production since the first crop of fruit starts a few years after planting. In high-density orchards the control of tree size is essential. It is possible to control the vigour and size of the tree by selecting suitable cultivars, by choosing rootstocks capable of controlling scion vigour and, finally, by applying deficit irrigation to reduce plant vegetative growth. Knowledge of tree water requirements is needed for precise irrigation scheduling. In this study, the dwarfing capacity of two Leccino clones, Leccino Dwarf (LD) showing low vigour, and Leccino Minerva (LM) highly vigorous, was investigated under two water regimens, well-watered ( T 100 ) and water deficit ( T 50 ). We analysed growth rates, dry matter production, gas exchanges and water relations of one-year-old plants of Leccino Dwarf (LD) and Leccino Minerva (LM), grown in pots in open fields. The two genotypes showed significant differences in vigour, demonstrated by measuring the trunk diameter, shoot length and leaf area; values were significantly lower in clone LD. Stem water potential, photosynthesis and stomatal conductance were similar in both genotypes under a well-watered regime; they decreased when subjected to water deficit with values significantly lower in LM clone during the summer months, indicating physiological differences among clones and that LD adapts better to water deficit.

This research aimed to determine the effects of cryo-maceration at different temperatures on polyphenol content during the winemaking process of Chardonnay wine. Samples of Chardonnay grapes were subjected to rapid cooling processes by direct injection of liquid CO2 to obtain final temperatures of 10.0, 8.0, 6.0 and 4.0 &deg, C and yield different batches of grape mash. Subsequently, each batch underwent the winemaking process to produce four different wines. The wines obtained were characterized by chemical analyses. We observed higher extraction of polyphenolic compounds with low-temperature cold maceration, particularly when the temperature was reduced from 10.0 to 6.0 &deg, C. Conversely, when the temperature was reduced below 6.0 &deg, C, the increase in polyphenol content in wine was negligible, whereas CO2 consumption increased. Furthermore, a numerical simulation was performed to determine the pipe length, L0, after which the temperature was constant. This condition is very important because it guarantees that after the length L0, the thermodynamic exchange between liquid CO2 and is complete, eliminating the possibility of liquid CO2 pockets in the cyclone.

Aims: Tests were carried out to assess the effects of early defoliation, cluster thinning and cluster cutting on the basic and nutritional composition of musts and wines of Vitis vinifera L. cv. Montepulciano.Methods and results: Both production and quality variables of the musts were evaluated. Antioxidant activity was determined on berries and on wines, as were the phenol and anthocyanin concentrations. The wines were compared by sensory evaluation. The results attested to a positive effect of the treatments on grape composition and on antioxidant activity in the berries.Conclusions: The tested treatments (DP = early defoliation; D3 = cluster thinning 30 %; D5 = cluster thinning 50 %; T3 = cluster cutting 30 %; T5 = cluster cutting 50%) increased both the soluble solids and the pH of the musts and enhanced the nutritional quality (based on antioxidant concentration) of both the grapes and the wine.Significance and impact of the study: The adopted techniques may be useful in cases in which yield control is required and/or the composition of the musts and wines needs to be modified based on the concentration of sugars in the berries. However, the variable response of the vines to the various techniques suggests that each cultural practice be evaluated in relation to specific oenological objectives.

Background: With this research an inertizing and cooling process for grapes cryomaceration has been set up. The process in question has been performed by an innovative plant that cooled the grapes rapidly in about 8 sec until they reached the set cryo-maceration temperature, using direct injection of liquid CO 2 . It works with a grape flow of approximately 2-3 tons/h, with a maximum thermal gradient of 20 K between the grape inlet and outlet temperature. For this plant a vibrating device was set up that allowed that only one grape cluster layer to be formed on the ribbon conveyor after the grapes had been put into the feedbox. A numerical model was set up for the cooling tunnel, and numerical simulations were performed to investigate the operative parameters of the machine in question. The numerical results were validated by means of experimental tests. Results: The wines obtained by using the considered plant (IW) were chemically analysed, and a comparison was performed with wines obtained with the same grape without the use of the plant (TW). All phenolic parameters were higher in IW wines, while other substances such as alcohol, reducing sugars, acids, and volatile acidity were less affected by the different winemaking technique. A deeper yellow colour was a direct consequence of the higher phenolic content of IW wines. Panelists preferred the IW wines, which had a richer, more delicate aroma. Conclusions: The study showed that careful exclusion of air combined with preventing oxidation during the cooling process, that is realized with the considered innovative cooling plant, effectively yields pleasing wines with more character.