To assess the adaptive potential of very early, early and early-medium flowering cultivars of ornamental peach, their frost resistance taking into account the rate of microsporogenesis, susceptibility to blossom blight, leaf curl and powdery mildew were assessed in connection with their use in breeding and landscaping. According to the results of freezing, it was revealed that the early-middle flowering cultivars subgroup showed greater frost resistance. When exposed to -16 °C in February, the number of live buds in different cultivars varied from 0 to 42 % in 2020 and from 13.64 to 95.65 % in 2021, because they were at later stages of development. The temperature of -10°C in March 2020 had a significant detrimental effect on the opened buds and blossoming buds of most genotypes. The maximum percentage of live buds (48.08-64.21 %) was noted in cultivars at the stage of the appearance of sepals. Frost -3°C at the end of March 2019 before flowering was weak: the number of live buds varied between 79.22-100 % in many cultivars. Three early-flowering cultivars with the highest frost resistance of generative buds (Lel, Frezi Grant and Ruthenia) were identified during February freezing and 3 cultivars (Lel, Miraisikl 2/4 and Ruthenia) during March freezing. Their use in regions with similar frosts in the late winter and early spring periods does not significantly reduce the ornamental value of plants. An assessment of susceptibility to the main fungal diseases showed that early-flowering cultivars are most sensitive to the causative agent of blossom blight. The cultivar Snezhnaya Koroleva showed the least susceptibility to the three studied pathogens, to two pathogens – Lel, Zhisele (to blossom blight and leaf curl) and Lyubava (to blossom blight and powdery mildew). This allows them to be more widely used in landscaping and, depending on breeding tasks, to be used in breeding as sources of tolerance.
