Exploring the morphometric and biochemical quality characteristics of local medlar (Mespilus germanica L.) genotypes in West Black Sea (Bolu) of Türkiye

Medlar (Mespilus germanica L.) is an underutilized fruit belonging to the Rosaceae family. In recent years, describing the physical and nutritional profiles of lesser-known crops, particularly fruits, has become a prominent area of research. In this context, the present study evaluated the morphometric characteristics and certain secondary metabolites of local medlar genotypes cultivated in the West Black Sea region of Türkiye. The results revealed that fruit weights among the genotypes ranged from an average of 11.43–30.43 g, with a coefficient of variation (CV) of 35.13%, indicating the highest variability among the morphometric traits. Conversely, the fruit flesh ratio was the most stable characteristic, with a CV of 2.19%. Among the phenolic compounds, chlorogenic acid was the most abundant, ranging from 3.89 mg/100 g to 7.50 mg/100 g, followed by gallic acid and protocatechuic acid. Malic acid was identified as the predominant organic acid, exhibiting the least variability across genotypes (CV: 16.67%). In contrast, organic acids generally displayed relatively high variability, with fumaric acid showing the greatest variation (CV: 62.67%). In conclusion, this study offers important insights into selecting suitable criteria for medlar breeding programs and recommends morphometric characteristics along with organic acids content as effective markers for differentiation.