Influence of Climate Warming on Grapevine (Vitis vinifera L.) Phenology in Conditions of Central Europe (Slovakia)

The impact of warming on the phenology of grapevine (Vitis vinifera L.) in conditions of central Europe was evaluated at the locality of Dolné Plachtince in the Slovakian wine region. In Welschriesling and Pinot Blanc model varieties, the onset of phenophases as defined in the BBCH scale over the period of 1985 to 2018 was observed. Based on the data obtained, the influence of the average and average maximum temperature and GDD on the onset of phenophases was evaluated. The results observed indicate earlier budburst by five to seven days, earlier beginning of flowering by 7 to 10 days, earlier berry softening by 18 days, and harvest dates advanced by 8 to 10 days on average. In both varieties, the highest influence of the average monthly temperature in March on budburst, the highest influence of the average monthly temperature and the average maximum temperature in May on the beginning of flowering, and the highest statistically significant influence of the average maximum temperature in June on the softening of berries was found. Warming observed in moderate climate conditions of northern wine regions in central Europe (Slovakia) has not yet caused changes in the grapevine phenology stable enough to require serious adaptation measures

Grape Quality Parameters in Western Carpathian Region under Changing Climatic Conditions as Influenced by Drought

Western Carpathians are historically the northern range traditional grapevine growing areas since the Middle Ages. The mean anual temperature has increased by about 1.1°C during the last century in Slovakia. Elevated temperature impacted the growing conditions of grapevine. Together with the increased temperatures, higher frequency of drought periods and parameters are evident. Traditional grape producing areas are facing new challenges. Except for the accelerated grapevine phenology, pathogene infection pressure and occurence of pests including new ones, as well as the quality of grapes influencing wine quality, are changing. In order to evaluate the drought impact on the quality parameters of grapes the locality of the Cultivar Testing Station in Dolné Plachtince which belongs to the Central Slovakian grape producing region was chosen. Interanual variability of the drought impact on the grape quality was evaluated according to Palmer drought severity index (PDSI). The 1990-2014 period was used as a basis for evaluation. The period with the phenological phase crucial for the grape quality formation was determined. Two groups of cultivars with different ripening periods were selected. Pinot Gris, Muscat Ottonel Weiss, Müller Thurgau represented the early ripening cultivars (OIV earliness code 4 and 5), whereas Grüner Veltliner, Riesling, Welschriesling represented the late ripening cultivars (OIV code 8 and 9) were used. The cumulative values of PDSI for the crucial periods were calculated. The PDSI values as well as the sugar and acid contents were correlated to find the strength of relation between them. Short drought periods did not influence the grape quality significantly, while long drought periods caused a decrease of the acid content and an increase of the sugar content. Though the tendency was clear, the correlation level was mostly low. The most sensitive period in this sense was July-September; however, it was influenced by the ripening term of individual cultivars. The results suggest the necessity of a thorough approach to cultivar selection, taking into account its vitality and ability to preserve a satisfactory acid content in grapes by the harvest date