LANDSCAPE-ECOLOGICAL BASICS OF SUSTAINABLE SPECIES DEVELOPMENT OF THE GENUS <i>MALUS </i>MILL. UNDER NATURAL CONDITIONS AND ANTHROPOGENIC ENVIRONMENTAL CHANGES IN THE TRANS-VOLGA-URAL REGION
The climate of the Trans-Volga-Ural region is not sufficiently favourable for the growth of fruit crops. For the development and conservation of species of the genus Malus, a certain set of landscape-ecological conditions is needed to compensate the disadvantages of climatic conditions. Fruit trees reflect the environmental impact in their habitus, so a biological survey allows us to determine the areas both suitable and unsuitable for gardens. A favourable microclimate for fruit plantations is created due to elevated relief elements excluding the southward direction of the slope exposition, protection by forest tracts and forest belts, available water sources near the plantations, and fertile soils. Species and varieties are also responsible for preservation and productivity of plantings. The most resistant to the climatic conditions of the region are Malus baccata (L.) Borkh., M. cerasifera (Spach) Likh. and M. prunifolia (Willd.) Likh. It is with the participation of these species that Uralic and Siberian varieties have been created showing high conservation and stable yield in the Trans-Volga-Ural region.