We investigated the effects of elevated temperatures on the photosynthetic characteristics and fruit quality of the ‘Mihong’ peach (Prunus persica) under high carbon dioxide concentrations based on climate change scenario RCP 8.5. We simulated three different temperature conditions (control; the average temperature in normal years in Jeonju city, C+3.4 °C, C+5.7 °C) and 700 μmol·mol⁻¹ CO₂ (expected in the mid-21st century). The average photosynthetic rates were 10.64, 10.21, and 8.18 μmol∙m⁻²∙s⁻¹ at C+3.4 °C, control, and C+5.7 °C, respectively. The chlorophyll content in the control and C+3.4 °C increased compared to that at the early stage of growth, but that of C+5.7 °C decreased rapidly. The fruit weight was the highest for C+3.4 °C (158.2 g), followed by C+5.7 °C (129.5 g) and the control (127.3 g). The shoot length increased at C+3.4 °C and C+5.7 °C when compared to the control, and there was no significant difference in the other growth characteristics. The carbohydrate content was the highest at C+3.4 °C, and the nitrogen content increased as the temperature increased. Moreover, the C/N ratio decreased as the temperature increased but there was no significant difference. The rate of floral bud differentiation decreased as temperature increased, and that of C+5.7 °C was the lowest due to the low C/N ratio, vegetative growth dominance, and early defoliation. Furthermore, the floral bud density was low in the C+5.7 °C treatment. These findings indicate that a temperature increase of 5.7 °C under 700 μmol·mol⁻¹ CO₂ conditions will negatively affect the physiological response and fruit quality of the early-maturing peach variety ‘Mihong,’ and yield is expected to decrease in the following year.

This study investigated developmental changes in phenolic compounds and condensed tannin structure in the berry skins of three table grape cultivars, ‘Rosetta’ (RT), ‘Shooting Star’ (SS), and ‘Hongju Seedless’ (HS), from flowering to harvest. Spectrophotometric analyses were used to quantify total phenolic, proanthocyanidin, polymeric tannin, and anthocyanin contents, while high-performance liquid chromatography coupled with thioacidolysis was applied to characterize flavan-3-ol composition and determine the mean degree of polymerization (mDP) of condensed tannins. Phenolic accumulation exhibited distinct cultivar-dependent developmental patterns. Total phenolics and flavan-3-ol monomers generally decreased as berries matured, whereas anthocyanins accumulated after veraison in RT and HS. Polymeric tannins increased during the early developmental stage and subsequently declined, while mDP showed an overall tendency to increase toward maturity, particularly in RT, although the effects of cultivar, developmental time, and their interaction on mDP were not statistically significant. HS maintained high flavan-3-ol concentrations during early development, whereas SS exhibited comparatively low phenolic accumulation together with relatively limited variation in mDP. These findings provide the first comprehensive characterization of developmental changes in flavan-3-ol composition, polymeric tannin structure, and mDP in newly developed Korean table grape cultivars and a structural basis for understanding cultivar-dependent phenolic changes during berry development.