Development of Wheat Plants Reinoculated with Azospirillum brasilense

Aims: The objective of this study was to evaluate the effects of Azospirillum brasilense reinoculation in the initial development of wheat plants, from seeds submitted to inoculation with A. brasilense and different forms of nitrogen fertilization in the previous crop.

Study Design: The experimental design was completely randomized in a 2x2x4 factorial scheme with four replications.

Place and Duration of Study: The experiment was conducted in a greenhouse in the municipality of Marechal Candido Rondon – PR. The weather is classified by Koppen as a Cfa, subtropical with well distributed rains during the year, hot summers and annual average temperature between 22 an 23°C.

Methodology: The first factor was characterized by seeds of cultivar CD 108 (Corbélia/PR) and CD 150 (Marechal Cândido Rondon / PR). The second factor was absence and presence of reinoculation with A. brasilense in the seeds, harvested in the previous crop (F2). The third factor was the fertilization in the previous crop: absence of fertilization to the haul and absence of A. brasilense at sowing (control); 120 kg ha-1 of nitrogen (urea) associated with A. brasilense; absence of fertilizer to the haul and application of A. brasilense and 120kg ha-1 of nitrogen with fertilizer NET (Nitrogen Efficient Technology) associated with A. brasilense. The morphometric variables were: aerial and root length (AL, RL), stem diameter (SD), number of roots and volume (NR, RV) and aerial and root dry weight (ADW, RDW). The inoculation carried out initially increased the performance of the wheat plants, approaching the Azospirillum treatments with fertilization, specifically regarding the similarity to AL, ADW, RL, NR, RV.

Results: The fertilization with 120 kg ha-1 of NET associated with A. brasilense contributes to the development of the plants aerial part of the cultivar CD 150, according to results of AL and ADW, reducing stem diameter, increasing root length and volume in the absence of reinoculation. While reinoculating, 120 kg ha-1 of urea associated with A. brasilense, provided greater number of roots, root length and volume. On the other hand, the CD 108 showed little interference in the aerial part of the plants with respect to fertilization treatments. For the cultivar CD 150, reinoculation increased shoot length, regardless of fertilizer and inoculant treatment, besides increasing root dry weight. For the cultivar CD 108, the reinoculation reduced root length and volume, and increased number of roots, regardless of the treatment of fertilization carried out during the initial harvest.

Conclusion: Reinoculation proved to be a process that interfered in the development of wheat plants, differently to cultivate CD 108 and CD 150.