Impact Of Late Frosts on Physico-Chemical Indicators in Two Sweet Cherry (Prunus Avium L.) Cultivars Grown in the Romanian Plain

Sweet cherry is a horticultural crop of major importance both nationally and internationally. Spring frosts are a limiting factor for quality yields, while data on the susceptibility of new cultivars remain scarce. Thermal variability during critical flowering and fruiting stages necessitates the assessment of cultivar resilience to thermal stress. This 2025 study at the Moara Domnească Experimental Station, in a 2021 plantation, evaluates sweet cherry resilience to thermal stress in a frost-prone continental climate. The study aimed to assess the resilience of sweet cherry cultivars to thermal stress from late frosts by comparing their morphological and physiological performance under subcritical temperatures. The research sought to identify highly adaptable cultivars suitable for cultivation under current climate change conditions. Two commercial cultivars of interest, 'Kordia' and 'Regina', were analyzed under similar soil and agricultural technology conditions. Post-frost assessments included fruit weight, size (height and diameter), firmness, pH, sugar content (%BRIX), titratable acidity, and dry matter, with data collected using standardized laboratory methods and statistical analysis, while meteorological conditions were monitored via an automated weather station. 'Kordia' showed superior fruit quality after late frost, with higher weight (6.87 g vs. 4.42 g), diameter (22.93 mm vs. 18.79 mm), height (23.64 mm vs. 20.58 mm), and sugar content (16.33 %Brix vs. 15.48 %Brix). Frost damage to buds was similar: 29% for 'Regina' (‘Gisela 5’) and 30% for 'Kordia' (‘Gisela 6’). Despite this, 'Regina' yielded more, indicating better production tolerance to frost. Differences in firmness, pH, and citric acid were minor. Overall, 'Kordia' excelled in quality, 'Regina' in yield under frost-prone conditions. Assessing sweet cherry resilience to late frosts supports climate change adaptation and informed cultivar choice. 'Kordia' offers high fruit quality for frost-prone markets, while 'Regina' ensures better yields in stable climates. Matching cultivars to site conditions can optimize profitability and reduce economic losses from frost damage.