Fusarium head blight (FHB), mainly caused by Fusarium graminearum, is a devastating disease of wheat (Triticum aestivum L.). Improvement of host resistance is an effective strategy to mitigate yield and quality losses. In this research, we used marker-assisted selection (MAS) and genomic selection (GS) to develop adapted wheat cultivars and make accurate selections to advance breeding for resistance to FHB. Overland_Fhb10 is a moderately resistant hard winter wheat cultivar with Fhb1. Backcross populations were developed between Overland_Fhb10 as a donor parent and six elite domestic breeding lines as recurrent parents which are NE14696 (very good native tolerance to FHB), NE14421, NE16562, NE15624, NE14434 and NE10478-1 (very good native tolerance to FHB and marketed as LCS Valiant) to introgress Fhb1 into advanced or modern adapted germplasm for potential release or use as parents. The diagnostic KASP marker conferring Fhb1 was used in the genotypic identification from BC1 to BC3 generations. Disease resistance was significantly improved for each genotype in each backcross population. NE14696 carrying Fhb1 showed lowest severity (SEV) in three backcross generations. In addition to improving NE germplasm with marker-assisted selection, genomic selection was considered as a feasible solution to save field screening effort and data loss under unsuitable environments. To evaluate the prediction accuracy of genomic selection, SEV and incidence (INC) were evaluated for 1199 winter wheat lines planted in 2015 to 2019. The phenotypes were evaluated in replicated and misted disease nurseries located at Mead or Lincoln, Nebraska. In total, 62,478 SNPs were obtained by genotyping-by-sequencing and fitted in the statistical model. The heritability (H2) of SEV and INC varied through years with an overall H2 at 0.53 for SEV and 0.82 for INC. The cross-validation accuracy of the population ranged from 0.22 to 0.42 for SEV and from 0.39 to 0.67 for INC. MAS and GS results indicate the potential to improve the breeding program to advance FHB resistant lines along with good agronomic traits.
ACKNOWLEDGEMENT AND DISCLAIMER
This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0206-4-011. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. This effort is being augmented and enhanced with phenotypic trials with Dr. Clay Sneller at Ohio State University initiated in 2020. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.