Evolution of methods for assessing and selecting winter wheat plants from advanced frost and winter hardiness in the Forest-Steppe of Ukraine

It is known that the success of physiological and breeding approaches to increase frost resistance depends significantly on fundamental research into the nature of plant damage during overwintering and the determination of new ways of evaluating and selecting the offspring of resistant genotypes. Many researchers believe that winter hardiness is a complex and variable property of a plant organism, which is determined by a large complex of physiological and biochemical features and anatomical and morphological peculiarities. In different regions where winter wheat is sown, there are specific conditions of the autumn-winter-spring periods. The percentage of plants of a specific variety that survived after freezing in artificial climate chambers does not always characterize their real resistance to adverse overwintering conditions. A more convincing indicator of plants resistance is to evaluate them in specially created extreme conditions of the natural environment with the combined effect of all changing environmental factors and obtaining the offspring of surviving plants. A retrospective analysis of the evolution of methods for assessing frost and winter resistance of winter wheat plants was carried out, and on this basis an energy-saving method of ecological assessment and selection of plants with increased frost and winter resistance was shown. The basis of this method is specially created extreme natural conditions, which will contribute to the assessment and selection of plants for frost and winter resistance. On the basis of long-term research specific technical and technological solutions have been determined for the development of such a method by using soil baths placed above the ground. On the basis of the analyzed methods of evaluation and selection of winter wheat plants, an energy-saving method of obtaining plants with increased frost and winter resistance in extreme natural conditions of the autumn-winter-spring periods was proposed. Key words: soil baths, winter wheat, extreme temperature conditions, frost resistance, winter resistance, climate change.