Infrared Thermal Imaging Enhanced Selection Intensity for Fusarium Head Blight Resistance in Soft Winter Wheat

ABSTRACT Development of Fusarium head blight (FHB)‐resistant winter wheat ( Triticum aestivum L.) varieties relies heavily on visual scoring for large‐scale field evaluations. However, visual assessment of FHB symptoms remains a bottleneck in FHB resistance breeding due to its inherent subjectivity. At a single‐spike scale under greenhouse conditions, a significant difference in radiometric temperature starting at 8‐day postinoculation was observed between resistant and susceptible genotypes. Radiometric temperature was then explored as an additional FHB‐related trait for field evaluations, given its ability to distinguish resistance and susceptibility at the single‐plant and single‐spike levels. Plot‐level radiometric temperature was generated by infrared thermal imaging using Flir E60 (Teledyne FLIR, USA), in the Michigan State University Wheat Breeding and Genetics FHB nursery with different sets of genotypes in 2022 ( n = 305), 2023 ( n = 398) and 2024 ( n = 309). Plot‐level radiometric temperature has shown potential as an additional trait in unsupervised K ‐means clustering, increasing selection intensity in resistance selections (cluster) by 0.6 to 1 unit when combined with visually scored FHB‐related traits. However, further considerations and caution are needed when scaling close‐range infrared thermal imaging for large‐scale field evaluations.