Phenological growth stages of sorboid group within Malinae (Rosaceae) according to the BBCH scale

The development of a unified system for monitoring the developmental stages of sorboid plants within the subtribe Malinae holds significant economic and ecological importance. The study aimed to develop a comprehensive phenological system for sorboid plants based on the extended BBCH scale. The research was conducted during 2024-2025 at the collection sites of the National University of Life and Environmental Sciences of Ukraine and covered 49 species-level taxa representing the genera Aria, Aronia, Cormus, Hedlundia, Micromeles, and Sorbus, as well as the nothogenera ×Amelasorbus, ×Arsorbus, ×Pyraria, ×Sorbaronia, ×Sorbocotoneaster, and ×Sorbopyrus. The methodology involved regular field observations of individual plants, with developmental stages documented through systematic in situ photography throughout the growing season. The development of the extended scale was based on the principles of the decimal BBCH coding system and incorporated refined morphological descriptors for both vegetative and reproductive organs. To account for secondary and tertiary growth cycles observed under recent climatic shifts, a dual-indexing system was implemented to document successive proleptic shoots. The proposed scale consists of eight principal growth stages, substantially adapted to reflect the specific biological traits of sorboid plants. Key modifications include improved descriptors for bud and inflorescence emergence, a numerical system for recording multiple growth flushes (stages 31-39), and a redefinition of late-season stages to emphasise structural and physiological markers, such as leaf fall and winter dormancy, rather than transient optical traits. This standardised coding system provides high precision for bioclimatic monitoring, winter hardiness assessment, and the international exchange of scientific data on sorboid genetic resources. The results of the study can be applied in practice for monitoring the development of sorboid plants in forestry, horticulture, and biodiversity conservation