Moisture effects on the prediction performance of a single-kernel near-infrared deoxynivalenol calibration

Fusarium head blight (FHB) is a serious disease in wheat that affects grain quality owing to the accumulation of mycotoxins such as deoxynivalenol (DON) in grains. Near-infrared (NIR) spectroscopy has been used to develop techniques to estimate DON levels in single wheat kernels to facilitate rapid, nondestructive screening of FHB resistance in wheat breeding lines. The effect of moisture content (MC) variation on the accuracy of single-kernel DON prediction by NIR spectroscopy was investigated. Sample MC considerably affected accuracy of the current NIR DON calibration by underestimating or overestimating DON at higher or lower moisture levels, respectively. DON in single kernels was most accurately estimated at 13-14% MC. Major NIR absorptions related to Fusarium damage were found around 1,198-1,200, 1,418-1,430, 1,698, and 1,896-1,914 nm. Major moisture related absorptions were observed around 1,162, 1,337, 1,405-1,408, 1,892-1,924, and 2,202 nm. Fusarium damage and moisture related absorptions overlapped in the 1,380-1,460 and 1,870-1,970 nm regions. These results show that absorption regions associated with water are often close to absorption regions associated with Fusarium damage. Thus, care must be taken to develop DON calibrations that are independent of grain MC.