Indirect selection for lower deoxynivalenol (DON) content in grain in a winter wheat population

Selection for Fusarium head blight (FHB) resistance and lower deoxynivalenol (DON) content is an important goal in many wheat-breeding programs worldwide. Preliminary screening for less severe FHB symptoms in the early segregating generations can be an important tool to assist breeders in determining which lines to advance to homozygosity. The objectives of this study were: (1) to test influence of plant height, heading date, presence of awns and number of spikelets per spike on FHB index and DON content and (2) to estimate the reliability of indirect selection for lower DON content based on FHB index. A Ruby x Frontana winter wheat population was spray inoculated with a spore suspension of Fusarium graminearum in 2001 and 2002. Plant height was significantly associated with DON content in both years; taller lines accumulated less DON than shorter ones. The moderately resistant lines, based on FHB index after inoculation, had a statistically lower DON accumulation compared with the highly susceptible ones (17.7 ppm vs. 20.6 ppm and 0.6 ppm vs. 2.0 ppm in 2001 and 2002) respectively. The results from this study suggest that selection for FHB resistance can be an indirect selection method for lowering DON accumulation in wheat grain. A breeder can identify and discard those early generation lines that are highly susceptible to FHB as they likely would have higher DON levels.