4.7.4. Seed Treatments, Growth Conditions and Experimental Design

Seed treatments were conducted by dipping the seeds for 30 min in the following suspensions: (i) actinobacterial strain CBQ-EA-2 at 1 × 108 spores mL<sup>−</sup>1; (ii) actinobacterial strain CBQ-B-8 at 1 × 108 spores mL<sup>−</sup>1; (iii) a mix of the actinobacterial strains CBQ-EA-2 and CBQ-B-8 at 1 × 108 spores mL−<sup>1</sup> global concentration; (iv) *T. harzianum* strain A-34 at 1 × 108 spores mL−1; and (v) Celest® Top 312 FS (Syngenta®; Basilea, Switzerland) prepared in a water suspension of 192 mL of active ingredient per kg of seeds. The latter chemical compound was included for comparison purposes. Additionally, seeds dipped for 30 min in SDW were also included as non-treated control seeds, and lots of non-treated seeds were sowed in plastic pots with inoculated soil (treatment (vi): positive control) as well as in plastic pots with non-inoculated soil (treatment (vii): negative control).

After more than 50% of the seeds emerged, seedlings were treated every three days by wetting the substrate with 1 mL of the respective biological treatment (actinobacterial or *T. harzianum*) adjusted to 1 × 108 spores mL−<sup>1</sup> until the end of the experiment [28 days after sowing (das)]. Both positive and negative controls and the chemical treatment were wetted every three days with 1 mL of SDW.

For each pathogen, a split-plot design was used with soil (*n* = 2; sterilized and nonsterilized) as the main plot factor and treatments (*n* = 7) as sub-plot factor; with ten pots (replicates) per treatment, and 4 seeds per replicate (*n* = 40). They were maintained in a CBQ greenhouse at 28 ◦C, 70% RH and 1100 μmol m−<sup>2</sup> s−<sup>1</sup> light intensity.
