Earliness, Yield, and Fruit Quality Attributes of Low-Chilling Peach-Nectarine Cultivars with the Application of Low Biuret Urea and Calcium Nitrate

Abstract

This study aimed to determine the effects of low biuret urea and calcium nitrate application on earliness, fruit set, yield, and fruit quality characteristics in ‘Astoria’, ‘Maya’ peaches, and ‘Garbaja’ nectarine cultivars. In the study, Bud Feed (low biuret urea 15%) and calcium nitrate (Calcium oxide 12% and total nitrogen 7%) were applied 35 days before bud break. In this study, flowering and fruit set, harvest times, fruit yield, and quality characteristics were evaluated. The source of temperatures used to calculate chill accumulation (expressed as hours below 7°C and chill unit) and growing degree hours was investigated. Bud Feed application provided earliness of 2 days in ‘Astoria’ and ‘Garbaja’ cultivars and 3 days in ‘Maya’ cultivar. This application was a positive effect on flowering and final fruit set in all cultivars compared to control plants. The application was more effective in increasing the yield per tree by 33.72% (Astoria), 41.00% (‘Maya’), and 52.18% (‘Garbaja’). Bud Feed application was improved fruit size in ‘Garbaja’ and ‘Astoria’ cultivars, whereas this application produced more intense fruit skin color in ‘Maya’ and ‘Garbaja’ cultivars. These results showed that bud feed application can be used to prevent yield and fruit quality losses in peach-nectarines in warm winter under Mediterranean climate conditions.