Varietal differences in resistance to spread of Fusarium head blight and its relation with grain mycotoxin accumulation in western Japanese wheat.

Fusarium head blight (FHB) is the most serious disease affecting wheat (Triticum aestivum L.) because of its impact on yield and grain quality and its associated mycotoxin accumulation. This study was conducted (1) to develop efficient methods to evaluate varietal resistance against fungal spread after infection, (2) to investigate varietal differences in resistance to FHB infection, FHB spread, and mycotoxin accumulation in 23 Asian varieties, and (3) to analyze relations among FHB-resistant types. Inoculation of Fusarium graminearum isolate, causing virulence to detached spikes, enabled evaluation of FHB spread in a shorter period and smaller space than conventional methods. Among the varieties, the FHB spread differed significantly. 'Sumai 3' and its derivatives showed higher resistance to FHB spread than other varieties. The FHB spread showed no significant correlation with FHB infection. It showed significant positive correlation with DON, but some varieties with high resistance to FHB spread showed moderately high DON. Results show that improved methods to evaluate FHB spread can be effective to screen numerous materials. The FHB resistance of western Japanese varieties depends mainly on resistance to FHB spread. For development of FHB resistant varieties, due attention should be devoted to DON. [ABSTRACT FROM AUTHOR]