Trends in the Biochemistry of Certain Cherry Varieties under the Influence of Climate Change

Abstract

The aim of the study is to determine the trends of change of biochemical indicators of some of the most popular cherry varieties as a result of climate change. This study examines the impact of climate change on the biochemical characteristics of cherry fruits in the Kyustendil valley (Bulgaria) for the period 2020–2025. Two standard cherry varieties were analysed -- Bing and Van. The biochemical indicators studied are total dissolved sugars, electrical conductivity, acidity, redox potential, total dissolved solids, and salt. The results show a distinct trend towards an increase in temperatures and a decrease in precipitation, leading to decrease in sugars and acidity and increase of electroconductivity and total dissolved solids for both studied varieties, as well as a disruption of the salt balance in drier years as the salt content is higher than the dissolved solids. The low electrical conductivity is due to the higher content of organic acids, which are part of the total dissolved solids (TDS), or to the presence of impurities, sediments, gases, and other degradation products resulting from anhydrous and wax appearance temperatures, suggesting that the cherry varieties studied are beginning to reach their maximum tolerance to heat and drought. Differences between the two varieties underline genotype-specific responses, with Bing showing stronger negative trends in sugar accumulation, while Van exhibited relatively greater biochemical stability. Correlation and cluster analyses confirmed the relationship between climatic parameters and biochemical indicators, emphasizing that temperature and water availability (water/salt balance) are key drivers of changes in fruit biochemical profiles.