Geographical Variations of Volatile Metabolites in Newhall Navel Orange Based on HS-SPME-GC-MS and Meteorological Factors

Newhall navel orange, a major citrus variety in China, shows considerable variation in fruit quality across production regions. To investigate the key factors driving the geographical variation, this study systematically compared the quality of Newhall navel oranges from 13 production areas and analyzed the relationships between volatile metabolites and climate variables. Our results revealed pronounced regional differences in both fruit physicochemical properties and volatile profiles. Total soluble solids, titratable acid content, and peel color parameters (L*, a*, b*) were identified as the core physicochemical indicators most strongly associated with quality variation. Using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), 106 volatile organic compounds (VOCs) were identified, of which 56 were selected as potential differential markers via partial least squares discriminant analysis (PLS-DA). Correlation analysis and partial least squares regression (PLSR) revealed that annual mean wind speed (AMWS), mean diurnal temperature variation at the expansion stage (MDTV-ES), and mean wind speed, total sunshine duration, mean diurnal temperature variation at the degreening stage (MWS-DS, TSD-DS, MDTV-DS) were important meteorological factors related to volatile metabolism. The study clarified the geographical variations in physicochemical characteristics and volatile profiles of Newhall navel oranges, as well as the key climatic factors linked to volatile metabolism, providing a crucial theoretical basis for site-specific cultivation planning, demarcation of high-quality production areas, and targeted quality regulation of citrus varieties.