Моніторинг погодних умов осінньо-зимового періоду та їх вплив на морозостійкість рослин ожини звичайної (Rubus fruticosus L.)

Abstract

Goal. To determine the resistance of blackberry varieties to low temperatures in field and laboratory conditions; to select the most resistant varieties and to investigate the influence of weather conditions on the state of their overwintering. Methods. Laboratory, field, analytical. Results. Weather conditions were monitored in the autumn–winter period of 2019/20 and 2020/21. It was established that the winter months of these years differ significantly in terms of temperature, amount, and type of precipitation. It was noted that the Cacanska Bestrna variety (12.2 points) was characterized by the highest level of frost resistance in field conditions. The average level of frost resistance was fixed for Heaven Can Wait (17.0 points), Loch Tay (14.5 points), and Triple Crown (19.2 points) varieties. The results of the experiment on freezing under artificial conditions showed that the bud and part of the stem on the section through the bud were the most vulnerable to low temperatures, and the middle part of the shoot was the least vulnerable. The buds of the Triple Crown and Loch Tay varieties experienced the least freezing during artificial freezing to–25°C, which indicated their potential frost resistance and more stable fruiting. Conclusions. Coming from the weather conditions in the winter, the period of 2020/21 was a good period for conducting field research on the frost resistance of blackberry varieties, which was characterized by significant temperature changes (minimum temperature in January –20°C, February — –18°C) and sharp thaws (up to +4.5°C). It was determined that the weather conditions of the winter of 2019/20 did not negatively affect the plants in field conditions. However, we assume that the autumn weather conditions of 2019 contributed to a longer period of growth of shoots, which caused a decrease in the resistance of plants to low temperatures. The potential level of frost resistance of the researched varieties under laboratory conditions of freezing to temperatures of–25 and–30°C was established.