Integrated Fruit Phenotyping and Electronic-Nose Profiling of Five Ilex Taxa from Eastern China for Germplasm Characterization and Utilization

Accurate characterization of closely related Ilex taxa is essential for the conservation, documentation, and utilization of plant genetic resources. In this study, five Ilex taxa from eastern China (Ilex rotunda Thunb., Ilex chinensis, Ilex cornuta Lindl. & Paxt., Ilex cornuta ‘Fortunei’, and Ilex latifolia Thunb.) were evaluated using an integrated framework combining fruit morphometric traits, CIELAB color parameters, and electronic-nose (E-nose) volatile fingerprints. Fruit transverse diameter, longitudinal diameter, single-fruit weight, fruit shape index, and peel color traits (L*, a*, b*, and chroma, C*) differed significantly among taxa (one-way ANOVA, all p < 0.001). I. cornuta produced the largest and heaviest fruits, I. chinensis showed the most elongated fruit shape, and I. rotunda exhibited the highest redness and chroma values. Chemometric analyses of E-nose responses further improved taxon discrimination and revealed clear divergence in volatile-response patterns. Trait-space relationships were broadly consistent with the preset phylogenetic framework, with I. rotunda showing the greatest divergence and I. cornuta and I. cornuta ‘Fortunei’ showing the closest similarity. These findings indicate that integrated fruit phenotyping and rapid volatile profiling provide a practical approach for Ilex germplasm identification, comparative evaluation, and resource documentation, with potential value for conservation planning and horticultural utilization.