149 Bulletin UASVM Horticulture, 68(1)/2011 Print ISSN 1843-5254; Electronic ISSN 1843-5394 Influence of Different Factors on the Quality of Wine Grape Varieties in some Areas of Romania in 2010 Mihai-Lucian LUNG, Nastasia POP, Florentina CIOBANU, Simona-Laura LAZAR University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticuture, 3-5 Manastur Street, 400372, Cluj-Napoca, Romania; mihai2lung@yahoo.com, nastpop@yahoo.com Abstract. Among the organic substances contained in the chemical composition of grape wine utmost importance for assessing the quality is given by the sugars and the organic acids. Sugar content in grapes is influenced by several factors, such as biological characteristics of varieties and growing environment. Among endogenous factors, the temperature influences most the grape sugar content, which is correlated positively or negatively with acidity. Thus the four varieties of wine under study, (Pinot noir, Fetească neagră, Fetească albă and Muscat Ottonel), grown in three areas, with very different environment conditions (Timişoara, Iaşi and Cluj-Napoca), were found positive correlations between the amount of carbohydrates accumulated, titratable acidity and temperature. The varieties have accumulated more carbohydrates in Timiş oara (Pinot noir 240g / l) and the fewest in Cluj-N (Fetească albă 181 g / l). One can observe a negative relationship between sugar and acid content. Keywords: grapes, quality, sugar, acidity, climatic factors, temperature INTRODUCTION The quality of the grapes at maturity is given by an optimal ratio between sugar and acidity, and a maximum concentration of phenolic compounds. In viticulture there are many factors that determine the quality of the harvest: climatic factors, soil, variety, technology management and the interaction of all those mentioned above. Obtaining high-quality crops require good knowledge of all these factors. The light plays an important role in grape maturation and quality influencing a number of physiological processes. This may influence fruit composition by thermal effects and chromatic photosynthesis, involving different frequency radiation (Smart, 1987). The most important environmental factor that is a limited character for the delimitation area and spreading culture of the vine is the temperature. This affects the life processes of vine by the temperature (lower thresholds, thresholds, higher optimum level, critical moments) and the amount of degrees of temperature (thermal balance global, active heat balance, useful heat balance). (Coombe, 1987, Pop, 2010). During maturation, the temperature plays a decisive role for the quality of grapes, including flavor and color with a significant effect on the characteristics of wines (Jackson and Lombard, 1993). Different level of water in the soil affects the quality of grapes and is reflected in the wine quality. Conradie, in 2002, shows that in regions with high rainfalls the ripening capacity of grapes is smaller. It was noted that in temperate regions which generally do not suffer from drought, a certain lack of water during the ripening period is favorable for the organoleptic qualities of wine (Riou, 1994). Riou et al. in 1994, developed an index of soil for water potential equilibrium, that gives information about the quality of grapes for wine for use in various macroclimate (Carbonneau, 1994). Taking into account even the most important descriptions of the wine growing regions climate (Bentryn, 1988), they may be available only as indices, being insufficient to analyze