ADAPTIVE MECHANISMS OF SORGHUM BICOLOR L. UNDER CLIMATE CHANGE CONDITIONS IN THE POLISSYA REGION OF UKRAINE

Abstract

Research has shown that current climate change, manifested in a steady increase in average annual air temperature and an increase in the frequency of hydrothermal anomalies, is causing a significant transformation of the agroclimatic conditions of the Polissya region of Ukraine and creating new challenges for the stable functioning of traditional agrocenoses. Analysis of long-term meteorological data for the Zhytomyr region has confirmed the trend toward regional warming and an increased risk of water stress during the growing season for agricultural crops. It has been proven that Sorghum bicolor L. is characterized by a high adaptive potential to changed hydrothermal conditions due to a complex of interrelated physiological and morphological mechanisms. The implementation of the C4 photosynthetic pathway, effective regulation of stomatal conductance, high water-holding capacity of assimilation tissues, and a well-developed root system ensure optimization of water balance, preservation of photosynthetic activity, and stability of the productive process under conditions of increased temperature stress and limited moisture supply. A comparative analysis of the physiological parameters of sorghum, corn, and winter wheat showed significant advantages of Sorghum bicolor L. in terms of water use efficiency, heat resistance, and productivity preservation under drought conditions. Higher values of water use efficiency, root system penetration depth, and photosynthetic activity temperature threshold result in lower yield losses of sorghum compared to traditional grain crops under extreme weather conditions. The results obtained indicate that, given the current climate changes, sorghum is no longer a crop exclusively for arid regions and can be considered a promising component of the agrocenoses of the Polissya region of Ukraine. Its introduction will contribute to increasing the adaptive resilience of agroecosystems, diversifying the structure of cultivated areas, and reducing the risks of crop losses associated with climate-induced droughts. The research has established that modern climate change, manifested in a steady increase in the average annual air temperature and an increase in the frequency of hydrothermal anomalies, is causing a significant transformation of the agroclimatic conditions of the Polissya region of Ukraine and creating new challenges for the stable functioning of traditional agrocenoses. Analysis of long-term meteorological data for the Zhytomyr region has confirmed the trend towards regional warming and an increased risk of water stress during the growing season for agricultural crops. It has been proven that Sorghum bicolor L. is characterized by a high adaptive potential to changed hydrothermal conditions due to a complex of interrelated physiological and morphological mechanisms. The implementation of the C4 photosynthetic pathway, effective regulation of stomatal conductance, high water-holding capacity of assimilation tissues, and a well-developed root system ensure optimization of water balance, preservation of photosynthetic activity, and stability of the productive process under conditions of increased temperature stress and limited moisture supply. A comparative analysis of the physiological parameters of sorghum, corn, and winter wheat showed significant advantages of Sorghum bicolor L. in terms of water use efficiency, heat resistance, and productivity preservation under drought conditions. Higher values of water use coefficient, root system penetration depth, and temperature threshold of photosynthetic activity result in lower yield losses.