Recurrent selection for Fusarium head blight resistance in a durum wheat population

Authors: WANG, RUNHAO - North Dakota State University; AXTMAN, JASON - North Dakota State University; LENG, YEUQIANG - North Dakota State University; SALSMAN, EVAN - North Dakota State University; HEGSTAD, JUSTIN - North Dakota State University; Fiedler, Jason; Xu, Steven; ZHONG, SHAOBIN - North Dakota State University; ELIAS, ELIAS - North Dakota State University; LI, XUEHUL - North Dakota State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2023
Publication Date: 12/30/2023
Citation: Wang, R., Axtman, J., Leng, Y., Salsman, E., Hegstad, J., Fiedler, J.D., Xu, S.S., Zhong, S., Elias, E., Li, X. 2023. Recurrent selection for Fusarium head blight resistance in a durum wheat population. Crop Science. 64(2):617-630. https://doi.org/10.1002/csc2.21179.
DOI: https://doi.org/10.1002/csc2.21179

Interpretive Summary: Fusarium head blight (FHB) is a devastating fungal disease that decreases yield and grain quality in durum wheat. The pathogen attacks during flowering and is difficult to control with fungicide usage. The development of elite durum that naturally combat the disease is the most efficient way to reduce risk for the producers, but this is limited by the complexity of the disease genetics and lack of strong durable genes in the available breeding stock. In this study, we utilized several modern breeding methods to quickly mix the genetics of diverse resistant lines and evaluate FHB resistance. Three cycles were completed in this study and the accumulation of many minor-effect and unknown resistance genes in the new germplasm resulted in a significant decrease in FHB severity, without creating negative genetic bottlenecks. FHB prediction using a small set of molecular markers was successful in this scheme and will accelerate selection in the future. These results are important because they provide a framework for breeders to improve resistance to a difficult disease incrementally, without sacrificing other traits, and will lead to improved elite durum cultivars.

Technical Abstract: Fusarium head blight (FHB) is a devastating fungal disease of wheat. Since 1990, frequent FHB epidemics in major wheat growing regions have caused massive economic losses. Developing FHB resistant varieties is key to alleviate the impact of the disease. In durum wheat, however, it is a challenge to develop FHB resistant varieties due to a lack of resistant sources. Introgression of resistance genes from wild relatives and bread wheat has resulted in some durum wheat lines with moderate resistance. Due to its complex genetic nature, integrating more resistance genes with major, moderate, and even minor effects promises to provide high and durable FHB resistance. In this study, we developed a base population containing diverse resistant lines and elite durum wheat breeding lines. Using this base population, we conducted three cycles of phenotypic selection for FHB severity, which decreased FHB severity by 34%. Six S0:1 lines in the Cycle 2 and Cycle 3 populations exhibited significantly lower FHB severity than the moderate susceptible check variety Riveland. Genetic diversity analysis of the Cycle 2 and Cycle 3 populations using 2,706 SNP markers indicated that there was no decrease in genetic variation due to selection. Genome wide association analysis found no markers significantly associated with FHB severity. Genomic prediction accuracies based on cross-validation for FHB severity, plant height, and days-to-flowering were 0.51, 0.69, and 0.61, respectively. Compared to recurrent phenotypic selection taking one year per cycle, recurrent genomic selection takes as short as four months per cycle and therefore is promising to accelerate genetic improvement of FHB severity.