Role of Morpho-Phenological Traits in Passive Resistance to Fusarium Head Blight in Wheat

Fusarium head blight (FHB) is a serious concern for wheat production worldwide. The current study was conducted to identify morpho-phenological traits that contribute to passive resistance against FHB. For this purpose, a set of 332 spring wheat genotypes from different origins was used. Eight morpho-phenological traits and FHB severity were evaluated using spray inoculation under field conditions in 2022 and 2023. A non-parametric test was performed to evaluate genotypic variation for all studied traits, revealing significant differences among genotypes across the two years. Correlation analysis demonstrated a strong negative association between FHB severity and phenological traits: days to heading (r = −0.43, p < 0.001), days to flowering (r = −0.39, p < 0.001) and a low to medium negative correlation between FHB resistance and spike length (r = −0.29, p < 0.001) and spikelets per spike (r = −0.26, p < 0.001) on average across two years. Furthermore, there was a significant negative but weak association between anther extrusion and FHB severity (r = −0.21, p < 0.001). Random forest regression analysis demonstrated that a complex of eight morpho-phenological traits predicted FHB severity with an accuracy of 65% in 2023 and 57% in cross-validation sets across two years. According to permutation importance analysis, days to flowering, heading, and anther extrusion had the highest contribution to FHB severity, and all three traits had a significant effect on FHB prediction.