Programa de Pós-Graduação em Agronomia

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Navegando Programa de Pós-Graduação em Agronomia por Autor "Alberton, Odair"

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    Biocontrole in vitro de Fusarium solani isolado de mandioca
    (Universidade Estadual do Norte do Paraná, 2017-03-29) Azevedo, Paula Fernanda de; Lescano, Luis Eduardo Azevedo Marques; https://orcid.org/0000-0003-0874-9211; http://lattes.cnpq.br/0477576296995064; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449; Matsumoto, Leopoldo Sussumu; https://orcid.org/0000-0001-5102-545X; http://lattes.cnpq.br/0857955043436449; Oliveira Junior, Admilton Gonçalves de; https://orcid.org/0000-0003-1556-5146; http://lattes.cnpq.br/0212864823556099; Costa, Christiane Luciana da; http://lattes.cnpq.br/6077810777420475; Alberton, Odair; https://orcid.org/0000-0002-4819-6669; http://lattes.cnpq.br/5399268772894807; Torres, João Pereira; https://orcid.org/0000-0002-7306-9872; http://lattes.cnpq.br/2582950118304206
    Cassava root rot causes substantial yield losses. Because management is difficult and few chemical fungicides are registered with the Brazilian Ministry of Agriculture, Livestock and Food Supply (MAPA), alternative control strategies are needed. This study aimed to evaluate the in vitro inhibitory activity of Trichoderma harzianum, biofertilizer, and 49 cave‑dwelling bacterial isolates against two Fusarium solani isolates, and to elucidate the principal mechanisms of biocontrol involved. F. solani isolates (F1 and F2) were obtained from cassava roots showing symptoms of fusarium root rot. Bioassays with T. harzianum and cave bacteria used the dual‑culture plate method. Sterilized biofertilizer was tested at concentrations of 2.5%, 5.0%, 10.0%, 20.0%, and 40.0%; non‑sterilized (raw) biofertilizer was tested at 0.3125%, 0.625%, 1.25%, 2.5%, 5.0%, 10.0%, 20.0%, and 40.0%, prepared by dilution in culture medium. Fungal cultures grown without biofertilizer served as controls. Plates were incubated at 25 °C under a 12‑hour photoperiod for 7 days. Mycelial growth was recorded daily by measuring colony diameter; values were used to calculate mycelial growth rate (mm day⁻¹), percentage growth inhibition, sporulation rate, and spore germination percentage. All bioassays used a completely randomized design and results were subjected to analysis of variance. Data from the T. harzianum assay were compared by t‑test (p < 0.05), dual‑culture results with cave isolates by Scott–Knott test (p < 0.05), and biofertilizer assay results by regression analysis and Tukey’s test (p < 0.05). F. solani mycelial growth ceased after hyphal contact in dual cultures with T. harzianum, consistent with mycoparasitism, although sporulation rate was not affected. Sterilized biofertilizer showed no biocontrol activity; however, non‑sterilized biofertilizer provided effective control at 2.5% concentration, inhibiting mycelial growth by approximately 64% and 85% for isolates F1 and F2 respectively. Spore germination declined as the concentration of non‑sterilized biofertilizer increased. Metabolites produced by the microbial community present in unsterilized biofertilizer were essential for its inhibitory effect. Isolates F1 and F2 were sensitive to 87.80% and 89.80% of the 49 cave bacterial isolates respectively, indicating strong potential as sources of antimicrobial compounds. In conclusion, the tested strategies offer promising alternatives for the in vitro biocontrol of Fusarium solani.