Determination of adaptive capabilities of various types, forms and varieties of apple trees based on endophytic and epiphytic microbiota indicators

The aim of the research was to identify the most resistant species, forms and varieties of apple trees based on the developmental specifics of the various types of microbiota. The research was conducted in 2014–2023 at the I. V. Michurin Federal Scientific Center, Michurinsk, Tambov region. The year of planting was 2009 with the planning scheme 6×3 m., the rootstock 54–118. The objects of the research are: Malus robusta species; forms 25–8, 64–143, and 54–118; varieties Korichnoe polosatoe, Orlovim, Iyulskoe Chernenko, and Slava Michurinska. The soil type was leached medium-power black soil with a loamy mechanical composition. Pseudomonas syringae bacteria prevailed in resistant plants: 96.6 % in Malus robusta hybrid apple, 89.3 % in Korichnoe polosatoe variety, and 88.7 % in 25–8 form, which is 9.7 %, 2.4 % and 1.8 % respectively, higher than the average value among the test subjects. In 64–143 form and Slava Michurinska variety, the indicators are lower than the average by 5.5 % and 4.2 % respectively. The yield of mixed microbiota in Malus robusta was not observed (0.0 %). Korichnoe polosatoe variety had an indicator below the average value by 0.7 %, in the form 25–8 by 1.3 %, and in the form 64–143 by 11.4 %, which is 4.5 % higher than the average. The magnitude of negative tests ranged from 3.4 % (Malus robusta) to 6.2 % (Iyulskoe Chernenko), which did not exceed the average value. Samples 64–143, 54–118 and Slava Michurinska had above-average values of 1.0 %, 2.0 % and 4.0 %, respectively. According to the complex of indicators of microbiota yield and the percentage of negative tests, Malus robusta, Korichnoe polosatoe variety and 25–8 form had a high potential for environmental resistance. They were recommended for further breeding for resistance to adverse environmental factors.