Effect Of Early Leaf Removal And Vineyard Characteristics On 'Zweigelt' Grapevines (Vitis Vinifera L.) In Different Sites

One of the greatest challenges of climate change is to prevent vineyards from the effect of adverse weather conditions by using different viticultural practices. Innovative solutions, such as defoliation at bloom, are often applied in quality vine growing. In addition to the positive changes in quality such as higher contents of anthocyanin and aromatic compounds, defoliation also plays a role in crop soundness due to a more favourable microclimate in the bunch zone. We set up our experiment in 2014 and 2015 at three sites in Hungary (Dunakeszi, Vac, Erdokertes) with 'Zweigelt' grapevines (Vitis vinifera L.). Defoliation was performed at the time of bloom, to examine its effect on yield, quality and botrytis infection. The year 2014 was very rainy, especially from ripening to harvest. Due to the frequent rainfall, the cluster zone did not dry up in either site, but we found significant differences between the sites in infection rates when we examined the characteristics of the plantations. Incidence and severity of botrytis varied between the sites, too. In the drier second year (2015), between the sites significant differences in botrytis incidence and rate could not be confirmed. We found that yield, cluster and berry weight were significantly different between the sites, though the rate of differences was not the same in the two years. The origin of must samples had an impact on titratable acidity and pH, but not on soluble solids in 2014, in the next year, however, there were opposite results. The location significantly affected the vine balance and the macronutrient contents of leaf blades. Based on our results in rainy years, the use of permanent cover crops to control botrytis should be considered.