Effects of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi on leaf nutrient status and chlorophyll of cutting-propagated hazelnut (Corylus avellana L.)

This study investigated the effects of plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on the leaf nutrient status of rooted hazelnut cuttings. Rooted hardwood and softwood cuttings of ‘Tombul’, ‘Çakıldak’ and ‘Okay 28’ cultivars were grown under greenhouse conditions for 1 year following basic fertilisation (BF) and inoculation treatments (BF + Bacteria and BF + Mycorrhiza). Results showed that while bio-inoculants generally improved the nutrient profile, the effects were particularly significant for phosphorus (P), potassium (K), calcium (Ca) and chlorophyll content, especially in the BF + M group. However, despite the treatments, nitrogen (N) concentrations across all groups remained below the sufficiency threshold, indicating that the applied N dose was insufficient for an annual growth cycle. The study demonstrates that while AMF and PGPR enhance the uptake of several key minerals, their effectiveness is influenced by cultivar and cutting type. For successful nursery production, bio-inoculation should be supported by optimised nitrogen fertilisation to ensure balanced plant nutrition.