Determination of Effects of Some Summer Pruning Applications on Yield and Quality Characteristics of Alphonse Lavallée (Vitis vinifera L.) Grape Variety

Grapes, one of the most delicious and refreshing fruits in the world, are a source of sugar, minerals, and vitamins. Summer pruning affects ripening, disease control, yield, and quality parameters by controlling the vine microclimate. In our study, leaf removal, fruit thinning, and cluster thinning and their combination were applied to the Alphonse Lavallée grape variety, aiming to improve yield, cluster, and berry characteristics. As a result of the applications, cluster and berry characteristics, SSC, pH, titratable acidity (TA), total phenolic content, antioxidant activity, and color parameters were examined. In our study, all summer pruning applications and their combinations caused increases in cluster and berry parameters (weight, length, and width) compared to the control. In addition to these, the SSC, pH, and maturity index increased and TA decreased. All these applications also increased berry detachment and skin rupture force, which have an important place in road resistance in table grape varieties. Significant improvements were also seen in the quality parameters of total phenolic content and antioxidant activity. In addition, there were increases in the lightness and chroma values that determine the fruit quality in table grapes. Considering all these data, the summer pruning applications we made had significant effects on yield and quality. It is thought that cutting a part of the clusters instead of the whole cluster will especially prevent the yield loss experienced in cluster thinning applications.