Promising drought-resistant and heat-resistant species and varieties of the genus Malus Mill. for creation of sustainable agrocenoses in the Trans-Volga-Ural region steppe

Abstract

The stability and productivity of horticultural agrocenoses depend on the adaptation of fruit plants to climatic and landscape-ecological conditions. To form profitable fruit plantings in the Trans-Volga-Ural region, it is necessary to select varieties with high potential resistance to drought. The purpose of our study is to study the drought- and heat resistance of species and varieties of the genus Malus Mill growing in the study area. To estimate drought-resistance, we identified: the water content of leaves, water deficit, the water-retaining ability for 2 – 6 hours, the water loss on average for 1 hour, and heat-resistance. 180 samples of the genus Malus kinds, sorts, and varieties were the study objects for two years. Stress climatic factors were not noticed in 2019; therefore, most of the studied samples received a high assessment of relative drought-resistance. M. fuska, M. zumi, M. kaido., M. baccata (Dubki), and clonal rootstocks Ural 1, Ural 5, Ural 8, Arm 18, OB 3-4, OB 4-3, 54-118 and others were among the most drought-resistant species and varieties of the genus Malus in 2019. The vegetation period of 2020 was abnormally hot and dry. According to the water content in tissues, many of the leading sorts and forms of 2019 showed lower results in 2020. M. denticulata, M. mandzschurica, M. sikkimensis, M. turkmenorum №4, M. turkmenorum №5, M. purpurea, M. zumi, 70-20-20, Ural 7, Volga 12. were noticed among the most resistant representatives of the Malus family in 2020.