Potential of resistance of ornamental apple varieties and forms to low temperatures

Abstract

Using the method of artificial freezing, the analysis of frost resistance of annual shoots of varieties, forms and species of ornamental apple trees in the middle of winter was carried out. The purpose of work was to evaluate the genotypes of apple trees in the ornamental genetic collection of the Michurin Federal Scientific Center on maximum frost resistance. Freezing was carried out at a temperature of –40°C after standard hardening –5°C and –10°C (each stage for five days). The rate of temperature decrease was 5°C per hour. After reaching the required temperature, the shoots were frozen for 18 hours. Genotypes with maximum resistance to temperature drop to -40 °C were identified. This is the variety of Jay Darling, who is not marked by defeats of the wood. The Royalty variety is characterized by resistance to low temperatures at the control level Antonovka Оbyknovennaya. The academician of the Russian Academy of Sciences N. I. Savelev obtained promising genotypes of ornamental apple trees using the frost-resistant Yakutskaya I form and columnar seedlings with high aesthetic value. A high degree of resistance was found in columnar ornamental forms 7 II-69 and 7 II-67 — wood damage did not exceed 0.4 points. Relatively high frost resistance with a degree of wood damage from 1.1 to 2.0 points was recorded in the species M. transitoria, selected seedlings 7 I-103, 7 II-68, 7 II-72, 7 II-58, 7 I-31 and in variety Professor Sprenger. The degree of freezing of the buds in all studied genotypes did not exceed 1.0 points, which indicates that the temperature -40 о С in the middle of winter was not critical for them. The selected genotypes can be successfully used in gardening and used in further breeding.