New Fusarium head blight resistant spring wheat germplasm identified in the USDA National Small Grains Collection

Fusarium head blight (FHB; caused by Fusarium graminearum Schwabe) is one of the most destructive wheat (Triticum aestivum L.) diseases worldwide. Sources of FHB resistance are limited. The objectives of this study were to screen selected spring wheat accessions in the USDA National Small Grains Collection for FHB reactions using FHB index, visual scabby kernel (VSK), and deoxynivalenol (DON) content. A total of 1035 spring wheat accessions were initially screened in unrepticated field evaluation nurseries in 1998 and 1999. Accessions with low FHB were selected as putative resistant materials and were tested in replicated trials from 1999 to 2002. After three or more years of evaluation, 73 accessions with resistance were identified, including 10 accessions previously reported as resistant to FHB. Selections from Europe had the highest percentage of resistance to VSK, followed by selections from South America and Asia. We concluded that there is diversity for FHB resistance in wheat. Fusarium head blight resistance identified from Europe appeared to be unique in that these accessions normally displayed a moderate level of disease in the field, but a higher level of resistance based on VSK and DON. The discovery of diverse resistant sources will provide diversity so that higher levels of resistance could be developed. The novelty and types of FHB resistance in these selections shoutd be further characterized using molecular markers and different inoculation techniques.