Hailstorms are typically localized events, and very little is known about their effect on crops. The objective of this study was to examine the physiological and vine performance responses to natural hail, registered four weeks after full bloom, of field-grown Thompson seedless (Vitis vinifera L.) grapevines, one of the most important table grape varieties cultivated in Greece and especially in the Corinthian region in northeastern Peloponnese. Leaf gas exchange, vegetative growth, vine balance indices, cane wood reserves, yield components, and fruit chemical composition were recorded from hail-damaged vines and compared with control vines. Visibly, the extent of the hailstorm damage was great enough to injure or remove leaves as well as cause partial stem bruising and partial injury or total cracking of berries. Our results indicated that natural hail did not affect leaf photosynthesis, berry weight, total acidity, and cane wood reserves but significantly reduced the total leaf area, yield, and the total phenolics of berries at harvest. At the same time, hail-damaged vines increased the leaf area of lateral canes and presented a higher total soluble solid (TSS) accumulation, while no effect on the next year’s fertility was registered. The present work is the first attempt to enhance our understanding of the vegetative yield, berry quality, and physiological responses of grapevines to natural hail, which is an extreme and complex natural phenomenon that is likely to increase due to climate change.

Climate is one of the main factors that significantly impacts the terroir of vineyards by directly affecting vine growth, yield, and berry composition, which, in turn, are key to the quality characteristics of the wines produced. Climate change poses new challenges, especially in insular regions where changing grapevine varieties is limited due to Protected Designation of Origin (PDO) rules. Cultivating vines at higher altitudes may prove to be a potential solution. This study aimed to investigate the phenolic potential of the skins and seeds of cv. ‘Fokiano’, cultivated at two different altitudes, namely, 200 m and 800 m, on the Greek island of Ikaria, during 2019–2021. The results showed that grapes from 200 m exhibited higher values for weight, length, and width, while those from 800 m exhibited higher berry water content and higher skin-to-grape ratios. In addition, higher values of anthocyanins, enhancing the grapes’ color and phenolic composition, were recorded in grapes harvested at 800 m. It is, therefore, evident that higher altitudes can help grapes exhibit higher anthocyanin content and titratable acidity. Consequently, the choice of an altitude can counteract the phenomenon of early ripening caused by climate change. Adaptation strategies based on the present study’s observations may constitute viable long-term recommendations for vineyard establishment, especially in insular regions where it is not possible to move geographically to northern latitudes.

In warm regions, such as in southern Greece, the climate change can lead to prolonged dormancy as well as to problems in bud dormancy (delay in breaking time, reduce the rate of budbreak, intensity of the phenomenon of acrotony, grapevine bud fall, disorders in bloom with intense blossom dropping, etc.), with a significant impact on the production of the vines. In these areas, it is necessary to apply chemical substances in order to break the dormancy and advance budbreak, especially when it comes to new table grape varieties, most of which are seedless. Another phenomenon which is observed on grapevines and is directly associated with budbreak is acrotony, where the apical buds of the cane break first compared to the middle and basal ones. Acrotony can constitute a problem because it can cause irregular grape ripening, different timing of various activities in the vineyard, which brings about higher cultivation costs. In this research, a new method to measure and evaluate the acrotony and its intensity on the latent buds of grapevine canes was described. The results of two chemical substances applied on table grape variety ‘Prime’ in order to advance budbreak were presented. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

The development of inter-row wildflower meadows in vineyards could restore and preserve biodiversity as well as enhance the local rural landscape character. Herein, the prospect of inter-row development of a wildflower meadow from spontaneous vegetation growing within a table grape ‘Sultanina’ vineyard was studied for two years through the effect of different intensities of harvest on the meadow composition, arthropod presence, and grape vine produce. Three harvest treatments (constant, periodic, and none) were examined. The growth (height and area of groundcover) and number of plants per species that composed the inter-row wildflower meadow as well as the insects found within it and on the grape vine plants were recorded. At maturity, the main quantitative (yield/vine) and qualitative characteristics (soluble solids, pH, and total titratable acidity) of the grapes were evaluated. Results showed that both the quantitative and qualitative characteristics of the grape vines did not differ between treatments. The inter-row vineyard meadow composition that constituted of 21 herbaceous species did not differ between the periodic- and no-harvest treatments. Insect pests hosted within the meadow did not pose a threat to ‘Sultanina’ grapes, although thrips within the inter-row meadow showed a preference for Convolvulus arvensis. The overall results suggest the application of either a periodic- or no-harvest on the spontaneous vegetation of a Mediterranean ‘Sultanina’ vineyard over two years and constitutes the development of inter-row wildflower meadows from spontaneous vegetations as an appealing and promising sustainable vineyard floor management practice for permanent use that needs to be further researched.

The goal of viticulture in Greece, where it is one of the country’s briskest economic activities, is satisfying grape yields. Nevertheless, owing to the ongoing climate change, that goal is impeded by a major obstacle in the form of an insufficient period of chilling temperatures which are becoming briefer. Consequently, the shorter period of cold leads to poor budbreak which, in turn, results in reduced yields. In order to meet the chilling requirements that several plants (including the grapevine) require for bud dormancy release, agronomists have resorted to treatments with chemical regulators. This study aimed at identifying and quantifying during eco-dormancy the individual phenolic compounds, together with their possible variations, in the latent buds of the ‘Prime©’ and ‘Ralli’ table grape cultivars. The study induced chemical stress by means of four different solutions, at three discrete dates per year, for three consecutive years. Phenolics were analyzed via HPLC. Their quantitative analysis showed variations both between the varieties and between the samples of those varieties. The analysis indicated that the phenolic content continued progressing during the annual growth cycle. Higher rates of increase in the phenolic content were observed in the first three days following each application, which implies an immediate stress response mechanism. Strong positive correlations were detected between several polyphenols. Luteolin, despite registering a positive correlation with quercetin, resveratrol, o-coumaric, did not do so with the remaining polyphenols. The results confirmed that chemically-induced stress conditions affect the phenolics content. Moreover, depending on the date of application, significant changes appear in the variations of those phenolics.

Fruits of the three Arbutus species native in the Eastern Mediterranean region, i.e. Arbutus andrachne, A. unedo and their natural hybrid A. × andrachnoides, collected from two different regions in Greece (Kalamos and Varympompi), were analysed comparatively in order to determine their phenolic profile and measure the antioxidant activity using two different single electron transfer-based assays, ferric reducing ability (FRAP) and 2,2-diphenylpicrylhydrazil radical scavenging capacity (DPPH). The pomological characteristics of the hybrid were similar to A. andrachne, while A. unedo had about 2.0-2.5 times larger fruits, with 20% more moisture being 175% heavier. All three species and their biotypes from the two areas had high phenolic content and antioxidant properties and were clearly pulled in different groups. Total flavanols scored a very strong correlation to antioxidant capacity. Highest total flavanols concentrations were found in A. andrachne fruits, while the hybrid had similar concentrations with A. unedo. In samples from Kalamos, concerning condensed tannins, total flavones, flavonols, phenolics and antioxidant capacity FRAP, as well as total anthocyanin and delphinidin 3-O-galactoside, the hybrid presented average values compared to the two parental species, while A. andrachne had the highest values. A strong correlation was found between ortho-diphenols and total soluble solids, as well as of total phenolics and flavonoids with total anthocyanins. The polyphenolic content and the antioxidant capacity varied in different biotypes. A. andrachne biotype from Kalamos showed the highest antioxidant capacity and anthocyanin potential. All A. unedo biotypes and A. × andrachnoides from Varympompi showed higher concentrations of ascorbic acid compared to the other biotypes.