Effects of Climatic Conditions and Genotypes on Vitamin C Levels in Stone Species and Apple Cultivars

Genetic and climatic factors influence the nutritional content of fruit, with vitamin C being a key component. Using HPLC, we quantified the amount of vitamin C in cherries, apricots, plums, and apples from 2022 to 2024. Contents ranged from 1.6 to 24.6 mg/100 g fresh weight basis (FW), with apples and plums displaying the highest coefficient of variation (32.53% and 45.25%). The highest content was consistently found in accession 'HL827', which exceeded 20 mg/100 g FW. Cherries reached up to 12.1 mg/100 g FW in 2023 ('13590'), but decreased to 1.9 mg/100 g FW in 2024 ('Jacinta'). Apricots showed high fluctuation, with 'Betinka', 'Candela', and 'HL08-052' exceeding the 30% variance coefficient. Accessions that remained stable ('HL96-266') maintained a low variance only. Plums were the most sensitive, experiencing low vitamin C content under hot and dry conditions. Regression analysis identified temperature (NTavg-20) as the dominant climatic driver in plums and cherries (R² = 0.999, <i>p</i> < 0.05 and R² = 0.995, <i>p</i> < 0.05) respectively, whereas apples and apricots showed negligible responses (R² ≤ 0.210). These findings underscore the importance of genotype/environment interactions at the local level and highlight the value of stable accessions as valuable resources for breeding cultivars with high and resilient vitamin C content.