Coating seeds with endophytic fungi enhances growth, nutrient uptake, yield and grain quality of winter wheat

The aim of this study was to assess whether seed coating with microbial consortium based on the arbuscular mycorrhizal (AM) fungus Glomus intraradices BEG72, Glomus mossae, and Trichoderma atroviride MUCL 45632 could improve seedling establishment, yield and grain quality (protein content and mineral composition) of wheat (Triticum durum Desf.). As a first step, a laboratory experiment was conducted in a growth chamber to verify the capability of seed coating with endophytic fungi to promote emergence and plant growth of wheat seedlings. Two additional experiments were carried out under open field conditions, to evaluate the effects of coating with beneficial fungi on SPAD index, chlorophyll fluorescence, yield, grain quality and mineral composition of winter wheat. In the growth chamber experiment, 17 days after sowing, the SPAD index, the number of leaves, shoot and root dry biomass of seedlings were significantly higher by 10.0%, 28.6%, 23.1%, and 64.2%, in coated as compared to uncoated wheat seeds. In the open field trials, use of the uncoated seeds led to a significant reduction in grain yield by 24.3% and 7.7%, during the first and second growing season, respectively, compared to the coated seeds. Grain quality of wheat, in particular protein content, K, P, Fe and Zn concentrations were improved by AM fungi and Trichoderma inoculation. Uncoated wheat plants exhibited a strong variation of yield between the two growing cycles (2.8 and 3.6 t ha-1 for 2011-12 and 2012-13, respectively) in comparison to coated seeds (3.7 and 3.9 t ha-1 for 2011-12 and 2012-13, respectively). The increase in grain yield and yield stability with coating seed treatment was associated with an increased level of macro and micronutrient uptake, higher SPAD index and photochemical activity of PSII. The application of coated seeds containing Glomus and Trichoderma can improve the crop performance of wheat in a sustainable way.