Influence of Genotype, Maturity Stage and Year on Surface Pitting Susceptibility and Related Physiological Traits in Sweet Cherry (Prunus avium L.).

This study investigates the resistance of sweet cherry (Prunus avium L.) accessions to surface pitting, a critical postharvest issue. A two-year analysis of 32 accessions and 3 cultivars, fruit chemical composition (total antioxidant capacity, anthocyanins, polyphenols, dry matter, and ascorbic acid), and maturity stages on pitting susceptibility was conducted. The damage index (DI) is a quantitative measure of fruit susceptibility to surface pitting after mechanical injury and storage; lower DI values indicate higher resistance, while higher DI values indicate greater susceptibility. The damage index (DI) in our study ranged from 1.18 to 2.87, with '10072' exhibiting the highest resistance (DI = 1.18 ± 0.20) and '16806' the lowest (DI = 2.87 ± 0.49). Biochemical analysis showed an inverse correlation between total dry matter content (TDM) and DI (r = -0.445, p < 0.001), with high-TDM accessions demonstrating lower pitting susceptibility. Ascorbic acid levels also negatively correlated with DI (r = -0.148, p < 0.01), as '10072' contained 41% higher ascorbic acid than '16806'. In contrast, total antioxidant capacity (TEAC) correlated positively with DI (r = 0.309, p < 0.001), suggesting that higher antioxidant levels may increase susceptibility. Maturity stages affected fruit chemical composition but did not significantly alter DI values (first maturity stage DI = 2.17 ± 0.56; second maturity stage DI = 2.19 ± 0.53, p > 0.05). Some accessions maintained stable resistance across seasons, emphasizing the role of genetics. These findings provide valuable insights for breeding strategies to improve cherry resistance to surface pitting. The identification of highly resistant accessions like '10072' offers promising candidates for breeding programs, while predictive chemical markers could aid rapid selection for enhanced postharvest quality.