INFLUENCE OF CLIMATE VARIABILITY ON GROWTH, YIELD AND QUALITY OF GRAPES IN THE SOUTH PART OF ROMANIA

The aim of this paper was to evaluate the trends of changes in climatic parameters and the effect of climate variability on vegetative growth, yield and quality of grapes in Bucharest (44°47'N; 26°07'E). There were examined the trends of changes in temperature, precipitation and the annual minimum temperature from 1961 to 2013 and from 1998 to 2013 - the production and quality of grapes of 'Feteasca regala' variety. Between 1961-2013 the annual temperature was higher than average with 1.00 C, in the growing season (April-October) the average temperature was higher with 1.10 C and in the summer time with 1.90 C. There were established correlations between some climatic parameters and pruning weight, yield, sugar accumulation, titratable acidity etc. The temperature increase was associated with higher must sugar content, especially in the summer (from June to August). Also, more frequency of the minimum harmful temperatures for grapevine (under -20°C) was observed during the last decade. Grape production was correlated with the precipitations from the period March-May, and those of summer negatively influenced sugar accumulation in grape berries. In the last 16 years (1998-2013) there was a significant increase in the values of Winkler Index; maximum yield of grapes was obtained at values of this index comprised between 1600 and 1800; when the value was higher, the yield and must acidity decreased significantly. Maximum grape yields were obtained at values of Huglin Index comprised between 2300 and 2500; at higher values, there were registered significant decreases of the yield and of the must acidity as well as increased accumulation of sugars in berries.