Plant Propagation

As part of the Biosavex project, I set up and managed propagation trials in a mist tunnel, handling batches of up to 1,000 semi-hardwood olive cuttings at a time across 4 cultivars — including hard-to-root varieties. I compared the rooting efficacy of 4 different growing substrates combined with 2 rooting treatments (IBA vs. Azospirillum baldaniorum Sp245 as a microbial alternative), confirming that the bacterial treatment performed comparably to the auxin standard across multiple cultivars.As an outcome of this work, I developed a rapid histological protocol that enabled early prediction of rooting treatment success within 20 days of application, significantly shortening the assessment window compared to standard end-point evaluation.The bacterial inoculation proved to be an effective substitute in several olive cultivars, showing particularly strong performance in traditionally hard-to-root genotypes.

Acclimation

In an organic olive farming context, where the synthetic auxin IBA is not permitted, we evaluated the effect of Azospirillum baldaniorum Sp245 as a rooting agent and biostimulant on young olive plants cv. Leccino following transplanting. Plants treated monthly with bacterial suspension (AZO, 10⁷ CFU/mL) over five months showed a 281% increase in total fresh biomass, a 151% rise in leaf number, and a mean leaf area of 430 mm², compared to significantly lower values in the untreated control (121%, 61%, 293 mm²). Chlorophyll content, a key indicator of plant physiological status, reached 68.9 SPAD units in AZO-treated plants versus 53.4 in the control. At the root level, AZO treatment more than doubled the number of primary roots (8.1 vs 2.8) and tripled secondary root count (287 vs 120) relative to the untreated control. Cell-free supernatant (CFS), tested as an alternative, produced no significant effects.These findings support the use of A. baldaniorum Sp245 in organic nursery systems as a viable substitute for non-permitted synthetic compounds.