Effects of climatic factors on the fruit quality of Diospyros kaki Thunb.‘Taishuu’

【Objective】Global climate change, characterized by rising mean temperatures and increasing frequency of extreme weather events, poses significant challenges to sustainable agricultural development and threatens the stability of crop production systems worldwide. Diospyros kaki Thunb.‘Taishuu’is a novel fruit cultivar characterized by its excellent mouthfeel properties and high economic value. However, this cultivar exhibits strict temperature sensitivity throughout its phenological development. Each growth stage of this cultivar requires a specific optimal temperature range, deviations from these thermal thresholds directly result in a decline in fruit yield and deterioration in quality, thereby constraining its commercial potential. In response to this issue, this study aims to elucidate the mechanistic impacts of climate change and extreme climate events on D. kaki‘Taishuu’fruit quality, identify the key meteorological factors driving fruit quality formation, and further enhance the environmental adaptability and stress resistance of this cultivar under climate change. This finding will provide a theoretical basis for ensuring the stability of fruit yield and quality.【Methods】Fruit development of D. kaki ‘Taishuu’was categorized into three distinct stages: the first rapid growth period, the slow growth period, and the second rapid growth period. This study was conducted across two production regions with significant climatic differences (Lanxi and Fuyang County in Zhejiang Province), and two years (2021 and 2024). Sampling was performed at 10-day intervals, starting from approximately 60 days after flow- ering (the middle and late stages of the first rapid growth period) until the fruits reached full ripeness. Climatic indicators and fruit quality parameters such as fruit size, fruit color indices, firmness, soluble solids content, glucose and fructose content, were determined in both production regions over the two study years. Comparative analysis was conducted to assess inter-regional and inter-annual variations in these parameters, followed by Pearson correlation analysis to elucidate the relationships between meteorological variables and fruit quality attributes.【Results】Pronounced spatiotemporal heterogeneity in climatic conditions was observed between Lanxi and Fuyang, as well as between the 2021 and 2024 growing seasons. Owing to topographic influences, Lanxi exhibited a localized high-temperature center, characterized by a mean temperature 2.5-3.1 ℃ higher than those in Fuyang during the fruit development period, while the precipitation was only 75.19% of Fuyang’s level. Conversely, Fuyang experienced an extreme high-temperature and drought event in 2024, with the daily average temperature and maximum temperature from July to August exceeded 2021 levels by 3.9 ℃ and 5.5 ℃, respectively, and the rainfall was only 16.25% of the 2021 baseline. The impact of climatic differences on the fruit quality of D. kaki‘Taishuu’showed distinct patterns: from the slow growth stage to the second rapid growth period, fruits from Lanxi County showed higher transverse and longitudinal diameters, fruit weight, fruit color, soluble solids, and sugar contents than those from Fuyang, albeit with marginally reduced flesh firmness. The fruit development in Lanxi was slightly earlier than in Fuyang, suggesting that a moderate increase in temperature can accelerate ripening kinetics. In 2024, the extreme high-temperature and drought stress induced systematic deterioration of fruit quality in Fuyang, specifically manifested by significant fruit weight reduction, inhibited fruit color development, decreased accumulation of glucose and fructose, and an accelerated decline in fruit firmness (P＜0.05). However, stable climatic conditions during late-stage fruit development enabled the final fruit size and quality to be comparable to those in previous years. Correlation analysis showed that significant correlations between fruit quality indices and meteorological factors (P＜0.05 or P＜0.01). Among them, the L* value was significantly positively correlated with temperature-related factors and solar radiation, while it showed an extremely significant negative correlation with air humidity; In contrast, the a* and b* values were positively correlated at significant or highly significant levels with air humidity and average evaporation, but significantly or extremely significantly negatively correlated with temperature-related factors; fruit weight and fruit firmness were significantly negatively correlated with various temperature-related factors and solar radiation.【Conclusion】Climatic conditions across diverse temporal and spatial scales exert significant regulatory effects on the fruit quality formation of D. kaki‘Taishuu’, with temperature, precipitation, and air humidity as the dominant meteorological factors. These findings provide a theoretical basis for optimizing cultivation management strategies by leveraging climatic variations, scientifically mitigating extreme weather stress, and enhancing fruit quality