Comparative Quality Evaluation of Jinggang Honey Pomelo Cultivars (Citrus maxima) at Two Developmental Stages

Jinggang honey pomelo (Citrus maxima (Burm.) Merr.), a regional cultivar group from Jiangxi Province, China, remains insufficiently characterized. This study evaluated morphological, peel-color, structural, edible, and physicochemical traits of ‘Jinlan’, ‘Jinsha’, and ‘Taoxi’ at immature (July) and commercial maturity (October–November) stages. The cultivars showed distinct developmental trajectories. At maturity, ‘Jinsha’ had the strongest late-stage growth (~186% fruit-weight increase; 9.0-fold flesh-weight gain) and high juice yield and edible rate. ‘Taoxi’ produced large fruits with the highest soluble solids content and titratable acidity, but retained substantial seed loads (69.15 ± 7.73 seeds per fruit). ‘Jinlan’ showed moderate enlargement but the highest mature-stage vitamin C content and retention. Peel-color development was cultivar-specific, with total color change following ‘Jinsha’ > ‘Taoxi’ > ‘Jinlan’. Within the local commercial harvest window, both soluble solids and titratable acidity increased, but the proportional increase in TA exceeded that of SSC, so the sugar–acid ratio declined in all three cultivars. Integrated principal component analysis (PCA) of 17 quantitative traits explained 82.51% of total variance in the first three components, confirming multidimensional quality differentiation jointly shaped by developmental stage and cultivar. These findings characterize cultivar-specific quality profiles, inform targeted market positioning, and provide a basis for future studies on harvest optimization and quality grading of Jinggang honey pomelo.