Submitted to: American Society of Agronomy Meetings
Publication Type: Other
Publication Acceptance Date: 5/20/2002
Publication Date: 8/20/2002
Citation: BALEY, J.G., KIDWELL, K., PAULITZ, T.C., YENISH, J., CAMPBELL, K.J. ASSESSMENT OF SOILBORNE DISEASE PRESSURE IN GLYPHOSATE TOLERANT WHEAT PRODUCTION. AMERICAN SOCIETY OF AGRONOMY MEETINGS. 2002. Interpretive Summary: Glyphosate tolerant, or Round-Up Ready wheat, has been genetically engineered to be resistant to the herbicide Roundup. Weeds and volunteers could then be sprayed out during the growing season of the crop. However, this killing of weeds and volunteers in the crop may have a greenbridge effect, and transmit soilborne pathogens such as Rhizoctonia and Gaeumannomyces graminis var. tritici. Roundup-Ready and non-herbicide tolerant cultivars were compared in inoculated greenhouse and field trials, to examine the potential risk.
Technical Abstract: Glyphosate tolerant wheat will permit in crop weed control while maintaining the intrinsic environmental and economic benefits associated with no-till crop production. However potential yield gains may be lost due to increased activity of soilborne pathogen on dying weeds within a glyphosate tolerant wheat crop. The objective of this study is to proactively determine the risks of incorporating glyphosate tolerant wheat into no-till production systems. Near isogenic lines (NILs), with and without glyphosate tolerance, of two spring wheat cultivars were evaluated under no-till conditions in three agroclimatic zones in Eastern Washington. A mixture of spring barley and sterilized oat seed inoculated with Rhizoctonia solani/oryzae or Gaeumannomyces graminis var. tritici (GGT) were direct seeded into the field plots prior to planting the NILs to simulate greenbridge volunteer. A no greenbridge control also was included. NILs from three treatments (RoundUp, Buctril/HarmonyGT, and a no spray control) were evaluated for disease severity as well as agronomic performance.