This study addresses the propagation challenges faced by ‘Shine Muscat’, a newly introduced premium grapevine cultivar in South Korea, where multiple viral infections pose considerable economic loss. The primary objective was to establish a robust in vitro propagation method for producing disease-free grapes and to identify effective plant growth regulators to facilitate large-scale mass cultivation. After experimentation, 2.0 µM 6-benzyladenine (BA) exhibited superior shoot formation in the Murashige and Skoog medium compared with kinetin and thidiazuron. Conversely, α-naphthaleneacetic acid (NAA) hindered shoot growth and induced callus formation, while indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) demonstrated favorable root formation, with IBA showing better results overall. Furthermore, inter simple sequence repeat analysis confirmed the genetic stability of in vitro-cultivated seedlings using 2.0 μM BA and 1.0 μM IBA, validating the suitability of the developed propagation method for generating disease-free ‘Shine Muscat’ grapes. These findings offer promising prospects for commercial grape cultivation, ensuring a consistent supply of healthy grapes in the market.

The storage capacity of ‘Cheonghyang’ grapes, a promising grape cultivar developed in South Korea, is a critical factor affecting their commercial viability. This study investigates the impact of salicylic acid (SA) treatment on the storage capacity of ‘Cheonghyang’ grapes. The effects of SA treatment at different concentrations were assessed by comparing fruit characteristics and enzyme activity related to shelf life after two and four weeks of cold storage in comparison with an untreated control group. The findings reveal that SA-treated grapes exhibited reduced water loss and improved firmness, leading to a lower occurrence of unmarketable berries. Furthermore, enzymes involved in pectin degradation, such as pectate lyase and polygalacturonase, were reduced in the SA-treated group, while antioxidant activity-related enzymes, including catalase, peroxidase and superoxide dismutase, were more active than in the control group. The most effective control of enzyme activities was observed at an SA concentration of 2 mM, which demonstrated the least decline in fruit quality among the tested SA concentrations in this study. These results indicate that SA is a highly effective substance for maintaining the storability of ‘Cheonghyang’ grapes under conditions of low-temperature storage after harvest.

Apple cultivars in Korea have been experiencing poor fruit sets due to early spring low temperatures and global warming. Therefore, the present study aimed to investigate the effects of temperature on fruit setting and to select apple cultivars tolerant to extreme temperatures based on the temperature response of their pollen. The effect of temperature on pollen germination percentage (PGP) and on pollen tube length (PTL) was determined under laboratory conditions using the pollen of ten apple cultivars. The two parameters were evaluated using a pollen germination medium, at temperatures ranging from 5 to 45 °C, at 5 °C intervals. The temperature variations considerably affected pollen germination and tube growth in all the examined cultivars. The maximum pollen germination percentage ranged from 61.5 (“Green Ball”) to 99.9% (“Shinano Gold”) with a mean of 85.2%, whereas the maximum pollen tube length ranged from 716.5 (“Tsugaru”) to 989.8 µm (“Arisoo”) with mean of 855.1 µm. There were differences in the cardinal temperatures (T_min, T_opt, and T_max) of PGP and PTL between cultivars. Mean cardinal temperatures T_min, T_opt, and T_max computed using the modified bilinear model were 4, 27.7, and 44.9 °C and 6.3, 28.6, and 43.7 °C for PGP and PTL, respectively. Our preliminary results may be used to select low-temperature and global warming-friendly apple cultivars for farmers and can also be exploited to develop temperature-tolerant apple cultivars during flowering.

Closed hydroponic systems for strawberries (Fragaria × ananassa Duch.) are infrequently used because the crop is highly sensitive to salt accumulation and prone to root diseases, resulting in yield reduction. This study investigated semi-closed hydroponic systems using various drainage recycling ratios (30%, 50%, and 70% of drainage EC) to determine their impact on yield, fruit quality, and antioxidant properties. Recycling at moderate levels (30–50%) effectively maintained ionic balance, particularly with respect to K/N and K/Ca ratios, which enabled stable yields and increased fruit weight similar to the control (open hydroponic system) group. Conversely, a high recycling ratio (70%) led to ionic imbalances—characterized by increased K/N ratios and higher concentrations of Na⁺, Cl⁻, and SO₄²⁻—that were associated with decreased fruit size. Measures of antioxidant capacity, such as total phenol and flavonoid content, ferric reducing antioxidant power, and DPPH activity, were not significantly influenced by the recycling ratio alone. Nevertheless, the relatively elevated antioxidant activity observed at the 70% recycling level indicates a mild ionic and osmotic stress response likely caused by increased salt concentration. Changes related to the cropping system season, rather than ion variations from recycling, exerted a stronger influence on antioxidant accumulation. In summary, moderate drainage recycling facilitates optimal fruit production without negatively affecting quality, while excessive recycling may increase antioxidant activity but leads to reduced yields. The results provide practical recommendations for optimizing nutrient reuse in semi-closed strawberry hydroponic systems.

This study investigated the influence of different electrical conductivity (EC) levels on cucumber growth and yield in pot soil under controlled conditions. Four EC treatments were tested: control, T1 (0.5 dS·m^-¹), T2 (1.5 dS·m^-¹), and T3 (2.5 dS·m^-¹), over a 53-day period. Irrigation and drainage dynamics were monitored alongside plant growth, fruit production, and leaf gas exchange. Plants in T2 and T3 required higher irrigation volumes but showed lower drainage rates (16.4%-17.2%), whereas the control and T1 required less irrigation but had higher drainage (24.8%-29.0%). Nutrient leaching was most pronounced in T3 at 51 days after treatment (DAT). Growth and yield parameters were significantly influenced by EC treatments: the highest plant height, leaf area, and fruit fresh weight were observed in T2 and T3 at 53 DAT, while T3 reduced fruit number and quality. Photosynthetic rate peaked in T3 (12.7 µmol m^-² s^-¹) but was associated with lower drainage pH and higher electrolyte leakage. In contrast, T2 improved overall growth and yield performance. Water use efficiency (WUE) was highest in T2 (2.82 g L^-¹) and lowest in T1 (2.22 g L^-¹). The highest Fertilizer use efficiency (FUE) was observed in T1 and the lowest in T3. Principal component analysis revealed that traits such as fruit fresh weight, fruit dry weight, leaf length, leaf width, leaf fresh weight, and leaf dry weight were strongly associated with T2. These findings demonstrate that a moderate EC level of 1.5 dS·m^-¹ optimizes cucumber productivity in controlled pot soil cultivation.

This study evaluated the growth performance and physiological responses of 24 Korean landrace accessions of pak choi (Brassica rapa subsp. chinensis) under polyethylene glycol (PEG)-induced drought stress to identify indicators for selecting drought-resistance genotypes. Electrolyte leakage (EL) and chlorophyll fluorescence (Fv/Fm) analyses showed that resistance accessions (IT262109(11), IT279432(12), IT293143(20)) had minimal increases in EL and maintained high Fv/Fm values under stress, indicating superior membrane stability and photosystem II activity. In contrast, sensitive accessions exhibited a sharp rise in EL and a decline in Fv/Fm to approximately 0.3 under 25% PEG treatment, reflecting severe physiological damage. Principal component analysis (PCA) biplot based on integrated growth and photosynthetic parameters differentiated resistance and sensitive groups, with PC1 representing photosynthetic efficiency versus membrane injury. Growth trait responses interaction analysis using GGE biplot of six representative accessions (three resistance, three sensitive) demonstrated that resistance genotypes had smaller positional shifts across treatments, indicating greater growth stability, while sensitive genotypes showed pronounced variability and environment-specific responses. This study provides a framework integrating growth and physiological indicators for identifying drought-resistance pak choi accessions, offering valuable implications for breeding programs aimed at climate-resilient cultivar development.