Sanitary and physiological quality of Delonix regia seeds inoculated with Trichoderma asperellum and Saccharomyces cerevisiae.

Abstract

Delonix regia is an ornamental tree species that is widely used in Brazilian landscaping. It is propagated by seeds, the quality of which can be compromised by the presence of pathogenic fungi. The use of biological agents, such as Trichoderma asperellum and Saccharomyces cerevisiae, in seed treatment has proven to be a promising alternative to the use of synthetic fungicides, promoting phytosanitary and physiological benefits to seeds. Therefore, the objective of this work was to determine the antagonistic effects of the agents T. asperellum and S. cerevisiae on the sanitary and physiological quality of D. regia seeds. The experimental design used was completely randomized, with treatments distributed in a 2 × 5 + 1 factorial scheme, with two biocontrol agents (T. asperellum and S. cerevisiae), five concentrations (0.0; 0.5; 1.0; 1.5 and 2.0 mL) + one additional treatment (seeds treated with fungicide). Seed health, germination, emergence and initial seedling development were evaluated. The fungi associated with the seeds were from the genera Fusarium sp., Cladosporium sp., Chaetomium sp., Aspergillus sp., Lasiodiplodia sp. and Rhizoctonia sp. The use of T. asperellum is effective in controlling Fusarium sp. in D. regia seeds, although its use may compromise physiological aspects of the seeds, such as germination and vigor. On the other hand, the application of S. cerevisiae was promising for reducing the incidence of microorganisms and, simultaneously, promoting improvements in the physiological quality of seeds. These findings indicate the potential of using biological agents, especially S. cerevisiae, as a sustainable strategy for the treatment of forest seeds.