Elucidating Sugar–Acid Metabolic Diversity and Screening Breeding Materials in Xinjiang Pear (Pyrus) Germplasm Resources

To elucidate the flavor substance basis of the pear germplasm resources in Xinjiang, this study conducted precise qualitative and quantitative analysis of sugars and organic acids in the fruits of 29 pear cultivars. Fructose and glucose are the dominant sugars, accounting for 64.0% of the total sugar content. Malic acid is the dominant organic acid, accounting for 85.8% of the total acid content. The cultivar LL exhibited the highest total sugar content at 633.6 mg·g−1, while cultivar JJL-1 showed the highest total acid content at 1441.3 μg·g−1. Early-ripening (ER) cultivars demonstrated significantly higher sucrose content compared to mid-ripening (MR) and late-ripening (LR) cultivars, while late-ripening cultivars contained the highest total acid content. These findings provide essential phenotypic data for understanding the genetic basis of sugar and acid metabolism in pear fruits and establish a scientific foundation for parent selection in breeding high-quality pear cultivars in Xinjiang.