Increased emergence of spring wheat after inoculation withPseudomonas chlororaphisisolate 2E3 under field and laboratory conditions

摘要

Inoculation at the time of planting withPseudomonas chlororaphisstrain 2E3 increased the emergence of spring wheat by 8 and 6 at two different sites in northern Utah. Isolate 2E3 strongly inhibited the growth of the wheat pathogenFusarium culmorumon artificial media. A second isolate ofP. chlororaphis(strain O6) also inhibited fungal growth on artifical media but did not increase emergence of the spring wheat at the same field sites. Inoculation of winter wheat by 2E3 did not promote emergence when planted into field soil sterilized by fumigation with methyl bromide. Under laboratory conditions, emergence of spring wheat in sterilized soils from both sites was at least 90. In the soils that were not sterilized, emergence was below 25 in soil from one site and below 50 in soil from the other. Treating seeds with 2E3 significantly improved emergence in a sterile soil-containing matrix that had been inoculated with the wheat pathogenFusarium culmorum. Consequently, we propose that increases in wheat emergence can be attributed to the suppression by 2E3 of pathogenic organisms present in the native field soils. A strain ofRhizoctonia solani, shown to the pathogenic on winter wheat, was isolated from one of these soils.