EVALUATION OF THE COLLECTORS' PEAR CULTIVARS AND HYBRIDS BY THE DEGREE OF RESISTANCE TO ELEVATED TEMPERATURES IN THE SUMMER PERIOD USING THE METHOD OF FLUCTUATING ASYMMETRY

The present paper uses the method of fluctuating asymmetry of leaf blades (FA) showing the possibility to determine pear reaction to high air temperatures in combination with a sharp deficit of summer precipitation. The objects of research are cultivars and hybrids of common pear (P. communis L.) and Asian pear (P. serotina Rh.) with different ripening periods. The work has been conducted in order to create a specific scale for assessing the adaptability and stability in pear development. The differentiation of cultivars and hybrids is shown according to their resistance degree to high temperatures in natural conditions, which makes it possible to optimize the breeding process, minimize crop losses and obtain genotypes with a high level of adaptation to hot and dry vegetation conditions.