COMPARATIVE EVALUATION OF ABIOTIC STRESS SUSCEPTIBILITY IN LOCAL AND INTRODUCED APPLE (Malus domestica Borkh.) CULTIVARS WITHIN THE ARID ECOSYSTEMS OF NORTHERN UZBEKISTAN

This research presents a rigorous comparative evaluation of the physiological susceptibility exhibited by twenty-one apple (Malus domestica Borkh.) varieties, encompassing both autochthonous and introduced germplasm, within the challenging ecological conditions of the Khanka and Khazarasp districts of Northern Uzbekistan. Spanning a three-year observation period from 2017 to 2019, the study utilized a standardized 5-point susceptibility scale to quantify the adaptive capacity of these cultivars against three primary abiotic stressors: drought, extreme atmospheric heat, and soil salinity. Notably, the local variety Sarapayan emerged as the most resilient genotype, particularly regarding salt tolerance (mean score of 0.95), while the Khazorasp and Shur olma series displayed exceptional stability under peak thermal and moisture deficits. Conversely, high-yielding introduced cultivars, exemplified by Reinette Simirenko, exhibited maximum susceptibility mean scores (exceeding 3.15 for salinity), indicating a precarious lack of physiological buffering mechanisms against the regional microclimate. The results suggest that while certain introduced varieties like Golden Grimes offer a moderate compromise in terms of adaptability, the strategic prioritization of local germplasm remains the most viable pathway for mitigating the detrimental impacts of climate change and soil mineralization in the lower Amu Darya basin.