Methods of Assessing Fusarium Damage to Wheat Kernels

Abstract

Fusarium Head Blight (FHB), or head scab, primarily caused by Fusarium graminearum Schw., is a destructive disease of wheat (Triticum aestivum L.). It has reemerged worldwide as a disease of economic importance. Damage produced by the fungus includes: reduction of yield, mycotoxin contamination (DON), discolored, shriveled “tombstone” kernels and reduction in seed quality. The disease also reduces the test weight and lowers the market grade. Thus, there is great interest among breeders in selecting for resistance to both traits of DON and fusarium damaged kernel (FDK). This study was conducted to determine the effect of mass selection for FHB resistance using an image-based optical sorter compared to other methods. Fusariun damaged kernel (FDK) percentage on a count basis is more accurate than the weight basis, which was obvious in the visual estimate method although they were highly correlated. Visually adjusting the scabby portion (output of air separation machine) increases the accuracy of FDK percentage. Moderate correlations existed between FDK and DON measured by using traditional methods (FDK on basis of visual estimate, FDK on basis of air-separation, traditional methods of DON measurement), NIR, and image-based optical sorter. DON was correlated better with FDK measured by the image-based optical sorter than FDK measured by the air separation machine, NIR, or a visual estimate. The image-based optical sorter is easier to run, not time consuming compared to other methods since the speed of sorting can be adjusted according to the user, and its ability to detect variation among the populations at 0.05 level of significance. Over the twenty populations tested, the data suggest that the image-based optical sorter effectively provides a better way to assess FDK and DON. This method could accelerate FDK and DON assessment, and can be a great tool for breeding programs to assess and select for low FDK and DON.

Keywords

• Fusarium head blight (FHB)
• deoxynivalenol (DON)
• Fusarium graminearum
• wheat