Effects of Conventional and Alternative Seed Treatments on Winter Wheat Establishment, Yield and Economic Performance

Sustainable alternatives to conventional seed treatments require validation under field conditions. This study compared two conventional chemical seed treatments (a fungicide and an insecticide) and three alternative treatments (a microbiological formulation, a plant-extract-based formulation and a biostimulant) with an untreated control in winter wheat over two growing seasons at ARDS Turda, Romania. The field experiment was arranged in a randomized complete block design with three replicates. Germination, crop establishment, cereal fly damage, yield components, grain quality and economic performance were evaluated. Data were analysed using linear mixed-effects models and Tukey-adjusted pairwise comparisons. All treatments significantly increased germination energy and germination capacity relative to the untreated control. Seed treatment significantly influenced field emergence and cereal fly damage but not tiller density or productive spike density. Biosem produced the highest field emergence (89.58%), whereas Bioseed was associated with the lowest incidence of cereal fly damage (4.02%). The overall treatment effect on grain yield was not significant (p = 0.063), although Signal 300 ES produced the highest yield (7909 kg ha−1) and differed significantly from the untreated control in the Tukey-adjusted comparison. Seed treatment significantly influenced thousand-kernel weight but not test weight, protein content, wet gluten content, or Zeleny sedimentation value. No significant growing season × treatment interactions were detected. Signal 300 ES generated the highest estimated net benefit, whereas Redigo Pro 170 FS achieved the highest return on investment. The alternative treatments did not differ significantly in grain yield from either conventional reference treatment, although this should not be interpreted as evidence of equivalence. Further multi-environment validation is required.