An Evaluation of Exotic Germplasm as Sources of Fusarium Head Blight Resistance in Bread Wheat (Triticum aestivum L)

Abstract

Fusarium Head Blight (FHB) has become a disease of increasing concern in all wheat growing areas and the evidence suggests that currently available varieties in Northwestern Europe are susceptible to this disease. The purpose of this experiment was to assess the FHB resistance status of exotic germplasm. Exotic entries were compared with three locally adapted, susceptible check varieties under field conditions over three seasons (1997, 1998 and 1999). The exotic germplasm exhibited extensive variation in response to inoculation with local ecotypes of Fusarium culmorum. Several entries were characterised by consistently low levels of plant symptoms, kernel symptoms and grain yield reduction. A further two exotics may merit further investigation as possible sources of novel tolerance or resistance mechanisms. In addition to this elite germplasm the exotic entries also included ones that were consistently inferior to the locally adapted, check varieties. Thus, despite the fact that all of this germplasm had been ranked as resistant to FHB by CIMMYT it was evident that this resistance was not always expressed under Irish conditions. These results highlight the necessity for local evaluation.