Evaluación in vitro de aislamientos nativos de Trichoderma como agentes de biocontrol y promoción del crecimiento inicial en soja

Abstract

This study evaluated in vitro native isolates of Trichoderma asperelum, Trichoderma harzianum and Trichoderma theobromicola as biocontrol agents of Fusarium semitectum Berkeley and Ravenel, Corynespora cassiicola
(Berk. and Curt.) Wei and Diaporthe/Phomopsis, and as initial growth promoters of soybean. T. harzianum was the best competitor for substrate. Two strains of T. asperellum (A1 and A2) showed significant production of solouble metabolites, capable of reducing the pathogen growth while T. theobromicola was good at producing growth inhibitors volatile metabolites. Antagonists showed parasitic effect by winding and forming hook shaped
structures. T. harzianum and T. asperellum covered the entire surface of the Petri dish and sporulated over the pathogen mycelium. T. theobromicola covered 50% of the surface of the plate and did not move over the pathogen
mycelium. Seeds inoculated with Trichoderma significantly increased the percentage of germination energy and T. theobromicola increased the germination power. However, the treatment had no effect on the length of the
radicles and seedstalks. Even thought, it induced a greater production of biomass, with roots and seedstalks dry weight significantly higher than the control.