Study of winter hardiness of cherry varieties and hybrid forms against the background of damaging factors of the winter periods 2018-2021
The results of study of winter hardiness of annual shoot tissues and generative buds of cherry varieties and hybrid forms of different genetic origin are presented in the article. The comparative study of winter hardiness of cherry varieties and hybrid forms was conducted in the natural conditions: in the conditions of action of damaging factors of mild, warm winters (winters 2018/2019 and 2019/2020) and in the conditions of action of damaging factors of severe winter (winter 2020/2021). The frequency of occurrence of wood, cambium and core freezing was estimated in the study of winter hardiness of cherry annual shoot tissues. It was determined that annual shoot tissues of cherry varieties and hybrids freeze slightly much more often at the unfavorable terms of severe cold winters. The core freezes more often, the cambium is much less common and the wood practically does not freeze. It was shown that varieties and hybrids obtained with the attraction of Maaka cherry have the best winter hardiness of annual shoot tissues. The best winter hardiness of all annual shoot tissues was shown by varieties Livenskaya and Novella and hybrid form 05-00 among all studied varieties and hybrid forms. The percentage of living generative buds, living rudimentary flowers in them, as well as the number of intact vascular bundles of generative buds were taken into account in study of winter hardiness of generative buds. It was found that the generative buds of cherry varieties and hybrid forms were slightly damaged in all three parameters taken into account in the conditions of mild, warm winters 2018/2019, 2019/2020. The generative buds of varieties obtained on the basis of the cherry sour gene pool are moderately hardy, and varieties and hybrid forms obtained with the the attraction of Maaka cherry are winter-hardy under the action of the damaging factors of a severe winter. The varieties Novella and ELS Surprise and hybrid form 05-00 showed the best winter hardiness of generative buds in all three parameters among all studied genotypes. Thus, the winter hardiness of most of the studied cherry sour varieties in the conditions of the Central region of Russia is medium, which makes it impossible to obtain stable high yields of this crop in the Russia Central region. It is possible to increase the winter hardiness of cherry sour varieties by involving hybrid forms derived from Maaka cherry in the synthetic breeding of this crop.