Abstract. The vineyard protection with plastic sheets alters the light microclimate influencing the vine physiology and the grape quality. A study has been undertaken on table grapes to test if colored plastic films (yellow and pink) may improve their physiological and reproductive parameters. In cv Victoria, which has not too much dense canopy, very high productivity and white berry, the only improvement was a higher berry sugar content obtained with the yellow film, but in correspondence with a lower theoretical grape yield. In cv. Black Magic, which has very dense canopy, medium-high productivity and black berry, the two colored films stimulated the leaf gas exchange, possibly due to a compensation for a lower vegetative growth; the yellow film improved some aspects of the skin color; the pink film enhanced the sugar/acid ratio and than the precocity.

The aim of the work was to evaluate the effect of different canopy structures, deriving from two trellis structures and three pruning methods, on berry internal temperature, juice composition and main skin phenol traits of cv Syrah grape. The work was done at the ARC Experiment Farm in Robertson, South Africa. The following treatments were compared: VSP (hand spur pruned cordon), mechanical pruning, and minimal pruning. For each treatment, on both row sides, four measurement clusters were installed, each consisting of 12 temperature sensors. Continuous berry temperatures were measured for three days during the maturation period, in the 2012 and 2013 vintage years. Temperature was recorded on either sun-exposed or shaded bunches. At harvest, berry weight, juice soluble solids and skin color intensity, tone and total phenolics were analyzed. Pruning methods and canopy structures affected berry temperature, especially in exposed clusters. During the sunniest day hours, berries showed higher temperature than the ambient air, reaching the highest temperatures (+9 °C at 11:00) in the berries of mechanically pruned vines. Increasing berry temperatures enhanced juice total soluble solid concentration in grapes of VSP/spur pruned and of mechanically pruned vines, with a greater effect on the former. Increasing berry temperature enhanced total skin phenol concentration in grapes of VSP/spur pruned and of mechanically pruned vines until 29-30 °C; higher temperatures showed a negative effect. Berry temperature did not affect total soluble solid and total skin phenol concentration in grapes of minimally pruned vines.

Plastic films used to cover vineyard change microclimate conditions aiming to advance or delay grape maturity according with the marked demand. The capacity of the covering materials to modify the greenhouse microclimate depends strongly on their radiometric properties. The films used to advance grape ripening must meet the following requirements: high transmissivity to solar radiation to increase the internal air temperature; high transmissivity in the Photosynthetically Active Radiation wavelength range to increase potential photosynthesis; low transmissivity in the long wave infrared radiation range to increase air temperature by reducing the thermal radiative losses; high transmissivity in the ultra violet ranges in order to promote fruit quality (colour and nutraceutic compounds). The aim of this paper is to study the radiometric characteristics of plastic films suitable for early harvesting in vineyard protected cultivation in European Mediterranean area. Several films, based on ethylene-vinyl acetate copolymer (EVA) and low density polyethylene (LDPE), were manufactured adding different light stabilizer systems. Laboratory tests were carried out on the films in order to evaluate their radiometric properties. The effect of the radiometric properties on ecophysiological leaf functioning (rates of stomatal conductance, transpiration and leaf net photosynthesis) was evaluated under the covering in the vineyard. The results highlighted that the LDPE based film, containing an experimental additive aimed at shielding the near infrared component of the solar radiation, induced good ecophysiological results by allowing the passage of a high fraction of photosynthetically active radiation.

A time series of Landsat 8 OLI (L8 OLI) multispectral images acquired between May 2013 and February 2016 were used to investigate vigour, vine and soil water content in a vineyard of Moscato Reale (syn. Moscato Bianco) sited in the Castel del Monte DOCG area. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were calculated and compared with vine midday stem water potential (ΨMDstem) and soil volume water content (VWC), to calibrate estimation models. Estimation models were calibrated using already existing ground observation datasets from previous ordinary vineyard management operations: ΨMDstem was measured at two different locations in vineyard at 6 different dates in summer 2014; VWC was continuously measured from June to October 2014 and from January to September 2015. Results showed that: a) vine stem water potential can be locally estimated with an accuracy ranging from ±0.046 (high vigour vines) to ±0.127 (low vigour vines) MPa; b) soil volume water content can be locally estimated with an accuracy of about ±1.7%. Medium resolution satellite imagery proved, therefore, to be effective, at vineyard level, to describe vigour, vine and soil water status and their seasonality. This is an important issue to focus on since, as Landsat 8 images are free, the entire process is economic enough to be consistent with cost and incoming of the farming system

The impact of cluster heterogeneity on mechanical properties, chromatic indices and chemical composition of Italia table grape berries sorted by flotation was evaluated in this study. The density sorting at commercial harvest permitted to get berries of different ripeness and relatively different quality attributes. Individually, some grape chromatic characteristics, physical characteristics (weight of the whole berry and berry skin), content and composition of reducing sugars, organic acids and phenolic compounds (flavanols of low molecular mass in berry skins) permitted to characterise and to differentiate berries belonging to different density classes. However, the tested mechanical properties were not related to the berry density. When the variables that significantly contributed to the berry differentiation were globally assessed, the chemical parameters related to sugars (142.3–164.4 g kg-1), content of skin oligomeric flavanols [46.3–137 mg (+)-catechin kg-1], berry skin weight (379–607 mg), yellow/blue colour component (26.31–29.96) and chroma (26.40–30.06) were the more representative.

In Europe there is an increasing consumer demand for residue-free, organically grown table grapes. Organic table grapes cultivation, however, is very delicate and experience to advice organic growers is still quite lacking. Table grapes vines (Vitis vinifera L.) are always grown with irrigation in regions, characterized by low rainfall and a high evaporative demand, as it occurs in Apulia region (Southern Italy). Moreover, only limited guidelines are available for managing irrigation to obtain optimum balance among vegetative growth, yield, quality in organic table grape production of Southern Italy. The objective of this study was to evaluate the effects of two irrigation regimes on ‘Italia’ table grape variety grown in Apulia according to organic European Community rules. In 2010, Italia grapevines grafted onto 1103 Paulsen and trained to tendone system received two irrigation treatments: 80% and 100% of estimated vine evapotranspiration ETc. The number of buds, shoots and clusters per vine was uniformed. Vine water status and stomata conductance were measured at berry set, during berry growth and at grape ripening. At harvest, yield components and berry quality were assessed. As expected, vines that received the lower irrigation volume showed the worse water status and stomata conductance and reduced the leaf area expansion. At commercial harvest (4th October), grapes produced by 80% ETc irrigated vines reached a slightly lower sugar concentration, but SST/AT ratio did not change. The grape yield was reduced as a result of a lower berry number per cluster and a lighter berry weight. Vines irrigated at 80% of ETc were less vigorous, as showed by their lower pruning weight; however, the Ravaz index did not change between treatments.

In Southern Italy, vineyards of early seedless table grape are always grown under irrigation and covered with plastic film to advance grape ripening. A trial was carried out in a commercial vineyard located in the Apulia region, on cv. 'Sublima Seedless' trained to “tendone” trellis system. Vines were covered with plastic film and applying different water regimes. The effects exerted by the irrigation regime on vine water status, vine ecophysiological activity and the productive characteristics were investigated. Three watering regimes were compared: WR1, WR2 and WR3 corresponding to 50, 100, and 80% of water lost by evapotranspiration (excluding effective rainfall). Irrigation was scheduled using the “water balance” method, starting after berry set. The radiometric properties of the plastic film were evaluated by means of laboratory tests. Stem water potential was measured at different phenological stages in order to evaluate crop water status. Leaf gas exchange was also measured. At commercial harvest, the main quantitative and qualitative yield parameters were determined. Water stress was evident since fruit set, as shown by midday stem water potential, and has significantly affected berry growth and fruit yield. Leaf gas exchange was more active with WR2 treatment. A yield reduction of 9 and 44%, due to both, bunch size and berry weight, was observed for WR3 and WR1 treatments, respectively, compared to WR2 treatment.

Abstract. The impact of different ripening stages on berry texture properties of sorted ‘Red Globe’ and ‘Crimson Seedless’ table grapes was evaluated. Density sorting at different harvest dates was utilised to obtain homogeneous samples for each ripening stage. At the same ripening stage, ‘Red Globe’ berries were more firm, cohesive, springy, chewy and resilient but less hard and gummy than ‘Crimson Seedless’. Particularly for cv. Red Globe, the choice of the ripening stage at harvest could be a determinant for the berry quality because riper berries were associated with higher skin thickness values (+25%). The berry hardness and gumminess of ‘Crimson Seedless’ decreased significantly during ripening (−50%), and these parameters were most influenced by the berry size. Conversely, berry cohesiveness can be used as a ripeness predictor of table grapes because the changes during the ripening process were independent of berry size. The peduncle detachment resistance of the berry in the Crimson Seedless grapes decreased to values lower than 3.4 N, negatively affecting the quality attributes of the berry.

The production and consumption of table grapes is worldwide increasing, encouraged also by the nutraceutical properties of this fresh fruit. Until the end of the XX century, almost all table grape varieties were local and/or autochthonous, while the main present varieties are crosses obtained by public or private institutions in all Continents. The changes of the ampelographic table grape platform is related to the market demand and, in particular, to the need of productive cultivars and grapes both attractive and resistant to the transport at long distance. Recently, the consumers are also looking for table grapes having a typical taste, different from that of the standardized international varieties, that, moreover, are often harvested before their full maturation, in order to reach the market as soon as possible and get the highest price. The local cultivars are well adapted to their specific environments, included the cool areas ; the best varieties could satisfy the particular consumer demand and be suitable for the so called ‘zero kilometer’ market.

Vineyard can be covered with plastic materials in order to protect vines and grapes from adverse weather conditions and to influence the microclimate, aiming at modifying the growing conditions in comparison with those in open field. This technique may advance berry ripening in table grapes. The radiometric properties of the plastic covering films influence canopy microclimate, leaf functioning, yield components and berry quality of grapevines. Three polyethylene films were tested in southern Italy in 2011: two commercial films, coded “YELLOW” and “NEUTRAL” according to their colour, and an experimental film coded “BASF”, as it was provided by BASF Italia Srl. The plastic films were tested on a seedless grapevine cultivar (Vitis vinifera ‘Sublima’) grown with a deficit-irrigation. The radiometric tests were carried out in laboratory. In the field, environmental parameters, such as photosynthetic photon flux, air temperature and relative humidity, were recorded. Moreover, the main parameters of vine ecophysiological activity, such as leaf gas exchange and vine water status, were investigated. At harvest, the vine productivity and the grape quality were assessed. The BASF and the YELLOW films were characterised by the PAR total transmissivity coefficient equal to 86.3 and 86.0%, respectively; the same coefficient was lower for the NEUTRAL film (81.8%). The YELLOW film was characterised by the highest solar IR transmissivity coefficient (90.0%), while the BASF film by the lowest one (81.0%). By analyzing the yield components, berry and cluster weight were found higher under the BASF film than under the other two types of covering films.

The use of covering nets is widely diffused in horticulture in order to protect plants from adverse conditions such as hail, wind or light excess, pest attacks, bird injury, hence, several type of articles are available. Most of nets are transparent/whte, aiming at allowing light penetration, or also black or green when shading effect is desired. In the last decade, photo-selective colored nets have been also experimented in order to assess the effects that the change in light spectrum may exert on leaf functioning, shoot growth and fruit quality. Nevertheless, all nets reduce the amount of light available for the crop; in many cases the leaf net photosynthetic rate is reduced, but, on the other hand, leaves and fruits are protected from damages caused by excess of irradiance. Besides decreasing incident solar radiation, nets modifies the crop microclimate in terms diurnal pattern of air temperature and humidity; they may lower daytime temperature and vapor pressure deficit, but increase night temperature, enhancing atmospheric stability. Under semi-arid conditions, to limit the solar irradiance at canopy level may be useful to lower the transpiration rate and thus the crop water deficit. Hence shade nets may be helpful to attenuate the effects of multiple environmental stresses. On table grapes, the net use of nets is quite largely diffused, but, on the whole, relatively little information is still available on their physiological effects on leaf functioning and grape quality. The most used net types reduce wind speed by 80-85%, and photosynthetic photon flux by 10-25% or even more, according to the net color. In many cases vine vigor and yield are increased; sometime, negative effects on berry characteristics have been noticed, such as a poorer skin color. To avoid possible detrimental effects, canopy management and other cultural practices should be adapted to match better the needs of vines grown under shade nets.

Astract. Black/red grapes are rich in phenol compounds. Many clinical studies have underlined the health benefits of consuming phenol-rich foods in order to reduce the risk of developing degenerative diseases. The berry phenols accumulation has a genetic base, but, its final expression is influenced by soil, climate, grape maturity and cultural practices. A trial was run in Southern Italy to assess berry skin phenols in three seedless cultivars, at a same degree of grape maturity (sugar concentration): Black Emerald (early ripening), Autumn Royal (medium-late ripening) and Crimson Seedless (late ripening). Moreover, the seeded cv Black Pearl was included in the study as a reference. It was evident that the two cultivars with darker berry skin color (Black Emerald and Black Pearl) accumulated a higher amount of phenols per gram of fresh berry, while the cultivar with lighter (red) skin color (Crimson Seedless) performed at the opposite; the cultivar with dark blue skin color (Autumn Royal) performed intermediately. However, the difference in phenol amounts was not limited to anthocyanins, but concerned also others phenol compounds. Autumn Royal and Crimson Seedless were also tested to evaluate phenol differences in grapes produced by “normallyirrigated” and “deficit-irrigated” vines. By comparing the phenol accumulation as related to the irrigation level, a genotype-irrigation interaction was noticed: grapes from deficit-irrigated Autumn Royal vines showed a moderate decrease in berry weight but a high increase in phenol amount per kilogram of grape, while Crimson Seedless, in this trial, did not show a relevant difference of berry skin phenols related to the irrigation level.

Abstract: Full-bodied and deeply colored red wines are presently the most appreciated and prized. Well-ripe grapes normally have a high glucidic content that gives highly alcoholic wines. Moreover, global temperature is increasing leading to advance in berry maturation and increase of sugar accumulation; this fact enhances even more the average wine alcohol content. Due to the consumer concern about the effects of high alcohol wine drinking, several producers have started to offer low alcohol wines. This type of wines can be produced by reducing alcohol in winery or by reducing sugar accumulation in berries. Within the last approach, different strategies have been suggested: selecting specific varieties or clones, increasing crop load, shading bunches, choosing proper irrigation techniques, modulating source-sink relationships by removing leaves or topping shoots, applying anti-transpirant to leaves or plant growth regulators to grapes. The results obtained from many studies are not univocal and are likely affected by the interaction between genotype and environment and by the extent to which each technique is applied.