Integración entre cepas de Pseudomonas protegens y fluquinconazole para el control de mal del pie en trigo.

Abstract

Mixing fungicides with bacteria that produce antimicrobial compounds is an integrated management tool that can reduce root rot pathogens such as Gaeumannomyces graminis var. tritici (Ggt), which causes take-all disease of wheat. This study analyzed the effect of wheat seed treatments on the survival of two strains of Pseudomonas protegens, when were applied to the seeds alone or integrated with fungicide a.i. fluquinconazole. Through three field experiments, under wheat monoculture and rotation, and inoculated with Ggt, the effect of bacterial combination with the fungicide seed treatment on yield components, above ground symptoms and root rot severity of take all disease was determined. In addition, bacterial populations were quantified using PCR and qPCR with phlD+-specific primers in wheat roots during tillering and anTesis during two seasons. P. protegens did not show marked effects on the evaluated parameters; however, when combined with fungicide, they increased yield, grain quality, test weight parameters, biomass, and plant heigh in early stage of plant development, decreasing also the severity of the disease. Initial populations of the bacteria were not affected when were co-treated with fluquinconazole, which was related with an early root colonization and protection in initial stages of development to stabilize their population during anTesis. Results suggest that integration of P. protegens strains with fluquinconazole is an alternative management strategie to reduce take-all disease in southern Chile.