EFFECT OF BIOLOGICAL PREPARATIONS ON THE BIOMETRIC PARAMETERS OF SCOTS PINE SEEDLINGS

The effect of pre-sowing seed treatment with biological preparations on the biometric parameters of Scots pine (Pinus sylvestris L.) seedlings was studied. The research object was Scots pine seedlings grown under different pre-sowing seed treatment regimes with biological preparations, while the research subject comprised the biometric parameters of the seedlings. The aim of the study was to determine the effectiveness of biological preparations based on qualitative and quantitative growth parameters of the seedlings. The study was conducted in 2023–2024, assessing seedling height, root collar diameter, length of the main and lateral roots, air-dry mass, and needle length. A total of 31 treatment variants were studied using minimum and maximum application rates of the biological preparations D–1, D–1A, D–11, D–11A, D–2, D–21, D–6, D–6A, D–7, D–7A, D–66, D–66A, D–555V, D–55, and Azogran; the control treatment involved soaking the seeds in water. The highest values for most biometric parameters were recorded for D–1 max and D–11 max at a dose of 5 mL/1 L of water. Under D–1 max, seedling height was 45.0±0.9 cm, root collar diameter was 3.4±0.15 mm, and air-dry mass was 43.8±1.1 mg, which were 91.5, 47.8, and 25.9% higher, respectively, than in the Control (23.5±0.5 cm; 2.3±0.08 mm; 34.8±0.7 mg). Under D–11 max, seedling height was 44.2±0.9 cm, diameter was 3.3±0.14 mm, main root length was 25.1±0.7 cm, lateral root length was 21.4±0.5 cm, air-dry mass was 43.2±1.1 mg, and needle length was 4.9±0.13 cm. In this treatment variant, the lengths of the main and lateral roots exceeded those of the Control by 132.4 and 23.0%, respectively. High values were also obtained for D–2 min (0.5 mL/1 L of water), D–21 max (5 mL/1 L of water), D–7 max (5 mL/1 L of water), D–555V max (4 mL/1 L of water), and Azogran (50 mL/0.5 L of water). Cluster analysis using Ward’s method demonstrated the differentiation of the treatment variants according to a set of biometric traits: the Control formed a separate cluster, whereas D–1 max and D–11 max were included in the group with the highest parameter values. The results confirm the potential of D–1 max and D–11 max for the production of Scots pine planting material.