Seasonal development rhythm of Pozdnyakov’s rowan-cotoneaster (Sorbocotoneaster × pozdnjakovii Pojark.) in the forest-steppe of the Ob River basin

Relevance. Pozdnyakov’s rowan-cotoneaster ( Sorbocotoneaster × pozdnjakovii Pojark.) is a narrowly local endemic of Yakutia, an intergeneric hybridogenic species of Pleistocene origin. It is included in the Red Data Book of the Russian Federation (status 3 a), and the Red Data Book of Sakha (Yakutia) (status 1). This fruit-bearing shrub contains bioactive compounds and is recommended for landscaping, particularly in settlements with harsh climatic conditions. Given this, the study aimed to investigate the effects of weather conditions on the seasonal development rhythm of S. × pozdnjakovii in the forest-steppe of the Ob River basin during its introduction process. Materials and methods. The study examined two introduced specimens of Pozdnyakov’s rowan-cotoneaster that had reached the generative phase under the forest-steppe conditions of the Ob River basin. Phenological observations were conducted following the guidelines by I. D. Yurkevich et al. To assess the relationship between the duration of phenological phases and climatic factors, a statistical analysis was performed using the StatSoft STATISTICA software package. Results and conclusion. The findings of the studies ascertained that Pozdnyakov’s rowan-cotoneaster plants, grown in the arboretum of the Siberian Research Institute of Plant Production and Breeding, passed through all developmental stages and should be characterized as a highly adaptable species, demonstrating significant acclimatization to the local climate. Variations in the timing of phenological phases were observed, with the earliest onset of plant growth in the dry year of 2022, and the latest in 2018, when the long and cold spring delayed the onset of phenophases. Correlation analysis identified the key climatic factors affecting the duration of different phenological phases. The most significant effect was exerted by the maximum and mean daily air temperatures, while the impact of precipitation was negligible for all phases.