Effect of Substrate Type and Arbuscular Mycorrhizal Fungi on Growth and Quality of Own-Rooted ‘Koroneiki’ Olive Nursery Trees
摘要
Arbuscular mycorrhizal fungi (AMF) are known to improve nutrient uptake and growth of perennial crops, including olive trees. In nursery systems, substrate type and microbial associations can strongly influence the establishment and quality of own-rooted plants. Evaluate the effects of different growing media and Rhizophagus intraradices inoculation on the growth and early vigor of own-rooted nursery trees of Olea europaea ‘Koroneiki’. A completely randomized design was used with six treatments consisting of different substrate compositions – commercial substrates (Carolina Soil®, Turfa Fértil®, and Beifort® S-10B) – combined with two fertilizer doses (1 and 3 g dm− 3 of controlled-release fertilizer), either with or without R. intraradices inoculation. Growth parameters assessed included plant height, stem diameter, leaf number, root volume and length, shoot and root fresh and dry biomass, shoot/root ratio, and Dickson Quality Index. Mycorrhizal colonization parameters (frequency and intensity) were also evaluated. Nursery tree height, root development, and biomass accumulation were significantly influenced by substrate composition and AMF inoculation (p < 0.05). Turfa Fértil® and Beifort® S-10B promoted greater height growth, while Carolina Soil® enhanced root volume and length. AMF inoculation improved dry biomass accumulation, particularly in Turfa Fértil®. The highest Dickson Quality Index values were observed in Carolina Soil® and Beifort® S-10B treatments, indicating greater structural robustness. Mycorrhizal colonization intensity was highest in Carolina Soil®, suggesting favorable conditions for AMF symbiosis. Carolina Soil®, with or without R. intraradices inoculation, and Beifort® S-10B proved to be the most effective substrates for enhancing early vigor and structural quality in ‘Koroneiki’ olive nursery trees.