Bio-ecological characteristics of Malus genus species in the context of prospective directions in horticulture and landscape forestry

The study aimed to conduct a comparative assessment of representatives of the genus Malus based on morphological traits, biological characteristics, physiological mechanisms of resistance to fungal pathogens, ornamental value, and significance within the frameworks of horticulture, landscape forestry, and shelterbelt afforestation. Employing an integrative approach, the research examined the morphological traits and biological characteristics of domestic apple, European wild apple, Siberian crab apple, hybrid crab apple, and plum-leaved apple. Comparative analysis was carried out to evaluate the susceptibility and resistance of these species to scab pathogens and other diseases. The findings indicated that the domestic apple is characterised by large fruit size, with an average fruit mass of no less than 150 g. In contrast, the average fruit mass for Siberian crab apple, cherry crab apple, and hybrid crab apple does not exceed 0.7 g, 1.8 g, and 3.2 g, respectively. The authors have developed an integrated scale for the comparative evaluation of Malus species (or crab apple varieties) based on overall ornamental value. This scale included five criteria: crown appearance, leaf aesthetics, floral attractiveness, fruit visual appeal, and resistance to apple scab. For the first time, fruits of different Malus species have been analysed for seed productivity. Among these, crab apple varieties, particularly the European wild apple and the plumleaved apple, were identified as having the highest average number of seeds per fruit – 10 and 8 seeds, respectively. It was also shown that the seeds of the wild apple are relatively large, with the 100-seed weight exceeding 3.9 g. The study highlighted findings that confirm the ornamental value of certain Malus species, notably the Siberian crab apple and the hybrid crab apple, which received the highest overall ornamental scores of 4.5 and 5. This contrasts with the European wild apple, cherry apple, and domestic apple, which scored lower for ornamental attributes (3.2-3.9). It was noted that crab crab apple species such as Malus sylvestris (L.) Mill. and Malus baccata (L.) Borkh. are wellsuited for use in the creation of forest-park landscapes. Under the conditions of the Northern Forest-Steppe of Ukraine, Malus species were differentiated by their resistance to the scab pathogen (Venturia inaequalis Cooke). The results established that domestic apple (cultivar Dozhnytsia), hybrid crab apple, and plum-leaved apple exhibited high resistance to this pathogen, which affects both foliage and fruit. The practical application of these findings lies in enriching the informational database on Malus species with updated data, enabling their utilisation in various thematic studies