Characterization and Bioactive Compound Analysis of 30 Jujube (Ziziphus jujuba Mill.) Accessions for Breeding Resource Development

Background: Jujube (Ziziphus jujuba Mill.) is a premier medicinal crop with a long history in traditional medicine, valued for its diverse pharmacological properties. Although the industrial demand for high-value bioactive materials is rising, the Korean jujube industry remains vulnerable because of its narrow genetic base. In this study, we evaluated 30 jujube accessions to identify superior genetic resources for the development of medicinal and functional cultivars. Methods and Results: Morphological traits, fruit quality, and antioxidant compounds were assessed over two consecutive years (2022 and 2023). ‘Gwangam’ produced the heaviest fruit (29.5 g), whereas ‘Wolchul-60’ exhibited the highest total soluble solids (29.4 °Brix). Physicochemically, ‘Sanjo’ recorded the highest vitamin C (1,472.5 mg/100 g DW) and total phenolic contents (TPC; 1,325.3 mg GAE/100 g DW), consequently displaying the strongest DPPH and ABTS radical- scavenging activities. Antioxidant capacity highly correlated with vitamin C content (p < 0.001). Fruit weight was negatively associated with antioxidant-related traits (r = -0.61 to -0.64, p < 0.001). Conclusions: The large-fruited ‘Gwangam,’ high-sugar ‘Wolchul-60,’ and vitamin C- and TPC-rich ‘Sanjo’ represent promising breeding materials for developing high-value jujube cultivars with enhanced functional quality.