The Effects of Nitrogen Fertilization on Quality and Antioxidant Compounds in Alphonse Lavallée Grape Varieties

This study, which aimed to determine the effects of different nitrogen doses (0, 50, 100, 150 and 200 kg/ha) on the quality of Alphonse Lavallée grapes, was conducted in the Keçiborlu district of Isparta in 2021 and 2022. The study was designed as a randomized block design with three replications. Quality analysis and determination of certain antioxidant compounds were conducted by measuring total soluble solid, pH, titratable acidity, maturity index, total phenolic content, total flavanol content, anthocyanin content and L-ascorbic acid content. The results of the two-year study showed that increases in nitrogen doses caused decreases in total phenolic, total flavanol, anthocyanin, total soluble solid, and the maturity index, while titratable acidity and L-ascorbic acid content increased.