Genomic prediction of Fusarium head blight resistance in early stages using advanced breeding lines in hard winter wheat

Fusarium head blight (FHB), also known as scab, is a devastating fungal disease of wheat that causes sig-nificant losses in grain yield and quality. Quantitative inheritance and cumbersome phenotyping make FHB resistance a challenging trait for direct selection in wheat breeding. Genomic selection to predict FHB resistance traits has shown promise in several studies. Here, we used univariate and multivariate genomic prediction models to evaluate the prediction accuracy (PA) for different FHB traits using 476 elite and advanced breeding lines developed by South Dakota State University hard winter wheat breed-ing program. These breeding lines were assessed for FHB disease index (DIS), and percentage of Fusarium damaged kernels (FDK) in three FHB nurseries in 2018, 2019, and 2020 (TP18, TP19, and TP20) and were evaluated as training populations (TP) for genomic prediction (GP) of FHB traits. We observed a moderate PA using univariate models for DIS (0.39 and 0.35) and FDK (0.35 and 0.37) using TP19 and TP20, respec-tively, while slightly higher PA was observed (0.41 for DIS and 0.38 for FDK) when TP19 and TP20 (TP19+20) were combined to leverage the advantage of a large training population. Although GP with multivariate approach including plant height and days to heading as covariates did not significantly improve PA for DIS and FDK over univariate models, PA for DON increased by 20％using DIS, FDK, DTH as covariates using multi-trait model in 2020. Finally, we used TP19, TP20, and TP19+20 in forward pre-diction to calculate genomic-estimated breeding values (GEBVs) for DIS and FDK in preliminary breeding lines at an early stage of the breeding program. We observed moderate PA of up to 0.59 for DIS and 0.54 for FDK, demonstrating the promise in genomic prediction for FHB resistance in earlier stages using advanced lines. Our results suggest GP for expensive FHB traits like DON and FDK can facilitate the rejec-tion of highly susceptible materials at an early stage in a breeding program.