National Horticultural Research Institute

Abstract Forest tree seeds are mass produced for afforestation and forest restoration programs, but are mostly underutilized beyond propagation. Here, we aimed to evaluate the antioxidant, anti-inflammatory, anticancer, and tyrosinase-inhibitory activities of seed extracts of seven economically important forest tree species in the Republic of Korea to explore their potential as multifunctional natural bioresources. The seed extracts of Alnus japonica, Chamaecyparis obtusa, Cornus kousa, Phellodendron amurense, Pinus densiflora, Prunus sargentii , and Quercus glauca were comparatively assessed using multiple in vitro assays. The results revealed clear species-dependent functional profiles rather than uniform bioactivities across species. Quercus glauca exhibited strong antioxidant activity and significant anti-inflammatory and tyrosinase-inhibitory activities, suggesting multifunctional potential, while C. obtuse presented considerable anticancer activity against several cancer cell lines. Alnus japonica exhibited the highest tyrosinase-inhibitory activity, followed by Q. glauca and C. obtuse ; A. japonica extract also showed a strong antioxidant capacity. Overall, the results demonstrated that forest tree seed extracts possess diverse and complementary bioactivities, supporting their potential as underexplored multifunctional natural materials. By focusing on seed resources generated within existing afforestation systems, we highlight a sustainable approach to valorize forest-derived by-products without additional pressure on natural ecosystems. Nevertheless, as bioactivities were evaluated using crude extracts, further studies are required to identify and elucidate the active compounds and their mechanisms of action.

In vitro culture of callus is an effective method for conserving the genetic resources of economically important crops. However, continuous subculturing is a costly and labor-intensive process. Therefore, establishing an efficient in vitro long-term conservation system applicable to various plant species is required. In this study, calli derived from five medicinal plant species, Camellia japonica (Cj), Centella asiatica (Ca), Ligusticum afficinale (Lo), Panax ginseng (Pg), and Sageratia thea (St) were used to optimize storage conditions and establish a suitable in vitro conservation strategy. Calli cultures were maintained on the appropriate culture medium at 5 °C for 120 days. Cell viability and regrowth rate were assessed during the storage period, and correlations between growth and antioxidant traits were examined. Subsequently, pretreatment optimization using sucrose (3–9%), MeJA (0-200 µM), and CTR (0–20 mg/L) was performed using RSM, and the effects of pretreatment and storage temperature on callus conservation were evaluated. In addition, machine learning models such as GRNN, MLP, RF, SVR, and XGBoost were applied to the experimental data. The findings demonstrated that, in comparison to Ca and St, Lo, Pg, and Cj exhibited noticeably higher antioxidant capacity while maintaining high cell viability and regrowth rates. Interestingly, Ca and St drastically decreased viability and regrowth after 60 days, whereas Lo, Pg, and Cj maintained viability and regeneration for up to 90 days. Both TPC and AC (measured by FRAP assay) showed a high positive correlation with cell viability and growth rate, according to correlation analysis. RSM predicted that the optimal pretreatment medium for enhancing antioxidant capacity was the species-specific proliferation medium supplemented with 3% sucrose, 135 µM MeJA, and 20 mg/L CTR, while the highest TSSC was achieved using the species-specific proliferation medium supplemented with 9% sucrose and 200 µM MeJA. When the storage temperature was set to 15 °C following the antioxidant-enhancing pretreatment derived from the RSM optimization, all five species showed improved cell viability and regrowth rates, among the storage methods. Among the ML models tested, XGBoost demonstrated the most stable and accurate predictive performance for both viability and regrowth during in vitro conservation. SHAP-based analysis of the XGBoost model, focusing on regrowth rate, revealed that storage duration was the most influential factor affecting regrowth prediction, followed by storage temperature, while pretreatment conditions showed secondary but meaningful contributions. This study demonstrates that long-term callus conservation is closely associated with AC and TPC. Medium supplemented with sucrose 3%, 135 µM MeJA, and 20 mg/L CTR, followed by storage at 15 °C, significantly improved viability and regrowth, and calli could be maintained up to 120 days without subculturing. This approach provides an efficient and broadly applicable in vitro strategy for the conservation of diverse plant genetic resources.

Hwan-Hee Bae, Young-Sam Go, Jae-Han Son, Jun-Young Ha, Jin-Seok Lee, Jung-Tae Kim, Seong-Hyu Shin, Yu-Chan Choi, and Tae-Wook Jung. Korean J. Breed. Sci. 2025;57:529-36. https://doi.org/10.9787/KJBS.2025.57.4.529

Prunus species exhibit physiological dormancy (PD), requiring dormancy-breaking treatments for successful germination in horticultural and ecological applications. Although stratification, gibberellic acid (GA 3 ) application, and endocarp removal are commonly used, their effectiveness varies by species and dormancy depth. Despite the ornamental and ecological value of Prunus maackii and P. virginiana , their dormancy characteristics remain poorly understood. This study evaluated seed dormancy characteristics and effective germination treatments for both species. Seeds and stones were exposed to four alternating temperature regimes, seven stratification treatments, four GA 3 concentrations with or without endocarp removal, and combined GA 3 and stratification treatments. Water imbibition tests indicated that both species lack physical dormancy (PY), and fully developed embryos excluded morphological dormancy (MD). In P. maackii , the highest germination rate (65.6%) was achieved through a warm and cold stratification regime consisting of 30 days at 20 °C followed by 60 days at 4 °C. In P. virginiana , the highest germination rate (70.8%) was achieved with warm and cold stratification (30 days at 20 °C followed by 90 days at 4 °C) combined with 1000 mg·L −1 GA 3 . Based on their responses to stratification and GA 3 treatment, P. virginiana was classified as having intermediate PD. In comparison, P. maackii exhibited characteristics of both nondeep and intermediate PD, indicating the presence of interspecific variation in dormancy types between the two species. These results provide species-specific protocols for improving the propagation efficiency of underutilized Prunus species.

Abstract Bisphenol A (BPA) is a pervasive endocrine-disrupting compound increasingly detected in wastewater effluents and reclaimed irrigation water, raising concerns for crop health and food safety. This study investigated the physiological, biochemical, and molecular responses of tomato (Solanum lycopersicum L. cv. Roma VF [NH5]) exposed to BPA-contaminated irrigation water under controlled greenhouse conditions at the Institute of Agricultural Research and Training, Obafemi Awolowo University, and the National Horticultural Research Institute, Ibadan, Nigeria. Plants were irrigated with 0, 50, 100, and 200 µg L⁻¹ BPA for 30 days, and growth, photosynthetic traits, oxidative stress biomarkers, antioxidant defense, and stress-related gene expression were assessed. BPA exposure significantly reduced plant height, chlorophyll content (SPAD), and photosystem II efficiency (Fv/Fm), with declines most pronounced at 200 µg L⁻¹. Lipid peroxidation increased by 171% relative to control,which indicated severe oxidative damage. Antioxidant enzymes (superoxide dismutase, catalase, peroxidase) and their corresponding genes (SlSOD, SlCAT, SlPOD) were markedly upregulated, reflecting activation of the redox defense system. Moreover, a 2.7-fold induction of SlHSP70 expression suggested generalized molecular stress responses and proteostasis disruption.Hence, these findings demonstrated that even environmentally relevant BPA levels can impair tomato plant growth and photosynthetic performance via oxidative and molecular stress pathways. Beyond productivity losses, the results showed that potential risks for food quality and human exposure under wastewater reuse practices. Monitoring and mitigation strategies are urgently needed to minimize BPA contamination in agricultural irrigation systems and safeguard both crop performance and food safety.

The aim of this study is to provide basic data on the yield and bioactive compound contents of the male asparagus cultivar ‘Avalim’ grown under two cultivation systems, i.e., an open field and a rain shelter house, in the Saemangeum reclaimed land. Spear sprouting, yield parameters, polyphenol and flavonoid contents, antioxidant enzyme activities (catalase, ascorbate peroxidase, peroxidase, and superoxide dismutase), and DPPH and ABTS radical scavenging activities of 22-month-old asparagus cultivated in each system were measured. Spear sprouting occurred approximately 10 days earlier in the rain shelter house than in the open field. The number of asparagus spears per 1000 m2 was approximately 600 higher in the rain shelter house, and the total weight was 21% higher than that in the open field. Polyphenol and flavonoid contents, antioxidant enzyme activities, and DPPH and ABTS radical scavenging activities were higher in the open field than in the rain shelter house. The temperature in the rain shelter house during the cultivation period was 0.6 to 17.4 °C higher than that in the open field, while light intensity was 359.7 μmol·m−2·s−1 higher in the open field. Consequently, cultivation in Saemangeum reclaimed land resulted in higher yields in the rain shelter house, whereas the bioactive compound levels were higher in the open field. Therefore, selecting an appropriate cultivation system based on the intended purpose, focusing on yield or functional quality, when cultivating asparagus on reclaimed land is important.

This study aimed to evaluate the effects of controlled atmosphere (CA) treatment on the postharvest quality of strawberries harvested at different 50% and 80% maturity under export shipping conditions. The strawberries were subjected to CA and refrigerated container (Reefer) environments at 10 °C, and their quality attributes were then analyzed. Metabolomic profiling revealed significant variations in primary and secondary metabolites and volatile organic compounds (VOCs). A pathway analysis revealed that CA conditions altered metabolic pathways related to sugar, amino acid, and energy metabolism during storage. CA treatment effectively delayed the accumulation of anthocyanins and enhanced the levels of specific amino acids and VOCs essential for the flavor and aroma of strawberries. Bioluminescence imaging revealed that CA treatment effectively reduced lipid peroxidation. A correlation analysis showed that certain VOCs and secondary metabolites significantly correlated with lipid peroxidation, indicating their role in enhancing antioxidant activity and reducing oxidative stress. These results suggest that CA conditions are associated with significantly reduced weight loss, the maintenance of firmness, and lower respiration rates in strawberries, particularly in those harvested at 80% maturity, extending the shelf life and improving the sensory quality of strawberries. Therefore, CA treatment is an effective method for long-term export.

Abstract This work introduces WISER (whitening and successive least squares estimation refinement), an innovative and efficient method designed to enhance phenotype estimation by addressing population structure. WISER outperforms traditional methods such as least squares (LS) means and best linear unbiased prediction (BLUP) in phenotype estimation, offering a more accurate approach for omics-based selection and having the potential to improve association studies. Unlike existing approaches that correct for population structure, WISER provides a generalized framework applicable across diverse experimental setups, species, and omics datasets, including single nucleotide polymorphisms (SNPs), metabolomics, and near-infrared spectroscopy (NIRS) used as phenomic predictors. Central to WISER is the concept of whitening, a statistical transformation that removes correlations between variables and standardizes their variances. Within its framework, WISER extends classical methods that use eigen-information as fixed-effect covariates to correct for population structure, by relaxing their assumptions and implementing a true whitening matrix instead of a pseudo-whitening matrix. This approach corrects fixed effects (e.g., environmental effects) for the genetic covariance structure embedded within the experimental design, thereby minimizing confounding factors between fixed and genetic effects. To support its practical application, a user-friendly R package named wiser has been developed. The WISER method has been employed in analyses for genomic prediction and heritability estimation across four species and 33 traits using multiple datasets, including rice, maize, apple, and Scots pine. Results indicate that genomic predictive abilities based on WISER-estimated phenotypes consistently outperform the LS-means and BLUP approaches for phenotype estimation, regardless of the predictive model applied. This underscores WISER’s potential to advance omics analyses and related research fields by capturing stronger genetic signals.