Exploring and exploiting the genetic variation of Fusarium head blight resistance for genomic-assisted breeding in the elite durum wheat gene pool

Abstract

Key message Genomic selection had a higher selection response for FHB resistance than phenotypic selection, while association mapping identified major QTL on chromosome 3B unaffected by plant height and flowering date. Abstract Fusarium head blight (FHB) is one of the most destructive diseases of durum wheat. Hence, minimizing losses in yield, quality and avoiding contamination with mycotoxins are of pivotal importance, as durum wheat is mostly used for human consumption. While growing resistant varieties is the most promising approach for controlling this fungal disease, FHB resistance breeding in durum wheat is hampered by the limited variation in the elite gene pool and difficulties in efficiently combining the numerous small-effect resistance quantitative trait loci (QTL) in the same line. We evaluated an international collection of 228 genotyped durum wheat cultivars for FHB resistance over 3 years to investigate the genetic architecture and potential of genomic-assisted breeding for FHB resistance in durum wheat. Plant height was strongly positively correlated with FHB resistance and led to co-localization of plant height and resistance QTL. Nevertheless, a major QTL on chromosome 3B independent of plant height was identified in the same chromosomal interval as reported for the prominent hexaploid resistance QTL Fhb1, though haplotype analysis highlighted the distinctiveness of both QTL. Comparison between phenotypic and genomic selection for FHB resistance revealed a superior prediction ability of the former. However, simulated selection experiments resulted in higher selection responses when using genomic breeding values for early generation selection. An earlier identification of the most promising lines and crossing parents was feasible with a genomic selection index, which suggested a much faster short-term population improvement than previously possible in durum wheat, complementing long-term strategies with exotic resistance donors.

Genome‐wide analysis and prediction of Fusarium head blight resistance in soft red winter wheat

“…Multivariate GS uses secondary traits that are genetically correlated with a trait of interest as covariates in a GS model, which can increase prediction accuracy, especially when the trait of interest has a low heritability and the covariate trait has a high heritability (Calus & Veerkamp, 2011; Guo et al., 2014; Jia & Jannink, 2012). Multiple studies have evaluated the use of MVGS for FHB resistance in wheat; however they have primarily focused on SEV as a trait of interest and only used HD and PH as covariates (Moreno‐Amores et al., 2020; Schulthess et al., 2018; Steiner et al., 2019). An MVGS model was also used to predict DON using an INC, SEV, and FDK index (Rutkoski et al., 2012).…”

Fusarium Head Blight and Rust Diseases in Soft Red Winter Wheat in the Southeast United States: State of the Art, Challenges and Future Perspective for Breeding

“…A recent study showed that the incorporation of the G×E effect and multiple traits in the GS model increased the prediction accuracy by 9.6% for low-heritability traits across environments (Ward et al, 2019b). Notably, the higher prediction ability of the phenotypic selection over GS with higher selection response vice versa documented by Steiner et al (2019) underscores that genomics and phenomics should be complementary to further cultivar improvements. Similarly, the higher accuracy of genome-wide maker-based models tested in recent studies to detect even minor effect QTL unchecked by MAS ensures the success of GS for future rusts resistance in SRWW (Todorovska et al, 2009;Bulli et al, 2016;Steiner et al, 2017).…”

Trichothecene Genotypes Analysis of Fusarium Isolates from di-, tetra- and Hexaploid Wheat

“…Interestingly, the smallest average number of Fusarium colonies was observed on the glumes and grain of durum wheat. There are many findings concerning the paucity of FHB resistance in durum wheats [39][40][41]. Thus, a low level of Fusarium infections on durum wheat grain and glumes may be an indicator of the potential resistance genes presence which might be useful in durum wheat breeding, however that should be investigated in more detail.…”