Fruit Quality Characterization and Comprehensive Evaluation of 30 Chionanthus retusus Accessions

Objectives: Research on kernel oil content and secondary metabolites in Chionanthus retusus was conducted to evaluate its potential as an oil crop. Methods: Fruits from 30 individual trees were collected to analyze morphological traits, oil content, and the composition of fatty acids, phytosterols, and tocopherols. Correlation, cluster, and principal component analyses were performed on the resulting data. Results: The mean fresh fruit weight, dry fruit weight, dry kernel weight, and kernel percentage were 77.02 g, 24.33 g, 12.22 g, and 51.14%, respectively. Kernel oil content averaged 35.83%, comprising seven fatty acids with oleic acid as the predominant component. Total phytosterol content reached 279.58 mg/100 g oil, with β-sitosterol being the major constituent among seven detected sterols. Total tocopherols were 571.13 μg/g oil, dominated by γ-tocopherol, indicating a potential antioxidant capacity. These components may reduce the demand for synthetic antioxidant food additives. A significant positive correlation was observed between kernel dry weight and oil content (r = 0.760, p < 0.01), supporting kernel dry weight as a key phenotypic indicator for high-oil breeding. Fruit quality traits did not cluster by geographic origin, whereas secondary metabolite profiles showed origin-based clustering. For breeding oil-producing C. retusus, select seeds with superior provenances based on secondary metabolites and cultivate them under optimal conditions to develop varieties with plump fruit, thereby boosting yield. Accessions WS-4 and WS-3 were identified as promising germplasm resources for oil production. Conclusions: The abundant oleic acid, β-sitosterol, and γ-tocopherol in C. retusus kernels highlight its potential as a woody oilseed crop.