Interaction between a peat carrier and bacterial seed treatments evaluated for biological control of the take-all diseases of wheat (Triticum aestivumL.)

摘要

Field plots were established in Indiana, Oregon, and Montana to evaluate the potential for biological control of various strains of bacteria as seed treatments to reduce the severity of take-all root, crown, and foot rot of wheat. The bacteria were grown in liquid broth Cas-amino acid broth media, mixed with finely ground peat, and applied to seed with methyl cellulose as a glue just before planting in field soils conducive for severe take-all. Autoclave-sterilized peat (minus bacteria) seed treatments increased take-all, immobilized Mn, and reduced plant vigor and grain yields. These effects were intensified when the pH of the natural peat was adjusted from 5.2 to 7.0 with CaCO3. The ability of the bacterial strains to counteract this peat-induced predisposition to take-all varied, and was influenced by planting site, genetic tolerance of the cultivar, and N treatment. Although the strains differed in their ability to suppress the peat-induced take-all, none of the isolates fully nullified the deleterious effects of the peat carrier. It is clear from this study that the carrier used with potential biological-contol agents may have a greater influence on disease than the biological agent.