Impact of Flower Thinning Using Ammonium Thiosulfate and Lime Sulfur on Yield and Fruit Quality of ‘Flariba’ Nectarine Cultivar

This study evaluated the effects of hand and chemical flower thinning on fruit set, yield, and fruit quality characteristics of the ‘Flariba’ nectarine cultivar under the ecological conditions of Tarsus/Mersin, Türkiye. Treatments included hand flower thinning (HFloT), hand fruit thinning (HFrT), and chemical applications of 2%, 3%, and 4% ammonium thiosulfate (ATS) and 3%, 4%, and 5% lime sulfur (LS). The effects of these treatments on fruit set rate, yield parameters, and fruit quality characteristics were assessed. The lowest fruit set rates were observed in HFloT (24.24%) and HFrT (29.65%). HFloT resulted in the lowest fruit load (2.41 fruits/cm²). The highest fruit weights were obtained in HFrT (105.57 g) and HFloT (105.18 g), followed by 5% LS (97.64 g) and 3% ATS (95.67 g), while the control trees had the lowest fruit weight (65.63 g). Both hand and chemical thinning improved fruit skin color compared to the control. In addition, HFrT, HFloT, and 4% ATS significantly increased the percentage of fruit in the first quality and extra class (97.17%, 83.00%, and 69.20%, respectively) compared to the control group (46.25%). As a result, hand and chemical thinning treatments enhanced fruit set regulation, yield, and fruit quality in ‘Flariba’ nectarines, with the 5% LS treatment being particularly effective in achieving moderate thinning, which could facilitate subsequent hand fruit thinning treatments.