Soils suppressive against Gaeumannomyces graminis var. tritici identified under wheat crop monoculture in southern Chile

Abstract

Improved knowledge of the biological phenomenon of soil suppressiveness is critical for the management and biological control of soilborne pathogens. Andisols, which are located in southern Chile, show very high conduciveness to the take-all disease of wheat caused by the fungal soil-borne pathogen Gaeumannomyces graminis var. tritici. However, no previous reports have investigated suppressive soils in this important wheat-producing area. The first part of this study was conducted to identify soils suppressive to the take-all disease, and will be followed by a characterization of its microflora to identify potential bio-control agents against the fungal pathogen. Based on the transferability of suppressiveness into the same sterile soil background, 20 soils were collected from different wheat-growing areas in southern Chile and were classified as either suppressive or conducive to the take-all disease under artificial inoculation in a greenhouse environment. Five soils were found to have highly suppressive properties to the take-all disease of wheat, and suppressiveness was observed in soils with a long history of wheat monoculture. Suppressive and conducive soils were found to have overlapping physicochemical characteristics. This is the first report of soils suppressive to take-all of wheat in Chile.