Genetics of Fusarium head blight resistance in soft red winter wheat using a genome‐wide association study

Abstract

Host resistance is an effective and sustainable approach to manage the negative impact of Fusarium head blight (FHB) on wheat (Triticum aestivum L.) grain yield and quality. The objective of this study was to characterize the phenotypic responses and identify quantitative trait loci (QTL) conditioning different FHB resistance types using a panel of 236 elite soft red winter wheat (SRWW) lines in a genome‐wide association study (GWAS). The panel was phenotyped for five FHB and three morphological traits under two field and two greenhouse environments in 2018–2019 and 2019–2020. We identified 160 significant marker–trait associations (MTAs) for FHB traits and 11 MTAs for plant height. Eleven QTL showed major effects and explained >10% phenotypic variation (PV) for FHB resistance. Among these major loci, three QTL were stable and five QTL exhibited a pleiotropic effect. The QTL QFhb‐3BL, QFhb‐5AS, QFhb‐5BL, QFhb‐7AS.1, QFhb‐7AS.2, and QFhb‐7BS are presumed to be novel. Pyramiding multiple resistance alleles from all the major‐effect QTL resulted in a significant reduction in FHB incidence, severity, index, deoxynivalenol (DON), and Fusarium‐damaged kernel (FDK) by 17, 43, 45, 55, and 25%, respectively. Further validation of these QTL could potentially facilitate successful introgression of these resistance loci in new cultivars for improved FHB resistance in breeding programs.

Multi-Locus Genome-Wide Association Studies to Characterize Fusarium Head Blight (FHB) Resistance in Hard Winter Wheat

“…The MTA S3B_768314878 for FDK was about 5 Mbp away from MTA S3B_773516625 that was identified for DIS in this study, suggesting a possible pleiotropic effect on both traits. As discussed earlier, previous studies also identified QTLs for different types of FHB resistance, including disease severity and DON at a similar position, suggesting this is an important region for FHB resistance on 3BL ( Dhariwal et al, 2020 ; Larkin et al, 2020 ; Ghimire et al, 2022 ). Similarly, MTA S5A_619020400 at 617 Mbp for FDK was found in the proximity of two previously reported QTLs, one for FDK mapped at ~596 Mbp in soft red winter wheat varieties AGS 2060 and AGS 2035 ( Castro Aviles et al, 2020 ), and another for DON mapped at 621 Mbp in a Canadian spring wheat cultivar AAC Tenacious ( Dhariwal et al, 2020 ).…”

“…Another MTA on chromosome 3B ( S3B_773516625 ) for DIS was mapped to 753 Mbp on RefSeq v1.0, which overlaps with the genomic region (~753 Mbp) for FHB type III resistance (DON) from a Canadian spring wheat cultivar ‘AAC Tenacious,’ validating the importance of this region ( Dhariwal et al, 2020 ). Recently, a GWAS using soft red winter wheat germplasm from the US also reported a QTL in similar 3B region associated with both type II and type III resistance ( Ghimire et al, 2022 ). Further, the MTA identified on 7AS ( S7A_48708273 ) was mapped in a close proximity to a QTL for type III resistance (~50 Mbp) in soft red winter wheat germplasm from southern US ( Larkin et al, 2020 ).…”

Separation of the effects of two reduced height (Rht) genes and genomic background to select for less Fusarium head blight of short-strawed winter wheat (Triticum aestivum L.) varieties

“…Although associated with FHB severity only, these QTL exhibited positive contribution to the interactions between the traits with about 16% of the genotypic correlation explained. Ghimire et al ( 2022 ) also reported five stable and pleiotropic QTL associated with FHB resistance and related traits such as DON accumulation and plant height in red winter wheat. Similarly, Schulthess et al ( 2017 ) reported the existence of genomic regions inducing pleiotropic effects on grain yield and related traits in wheat.…”

“…Effects of the genomic background on FHB severity and anther retention can be efficiently evaluated by calculating the genomic estimated breeding values (GEBV) of genotypes based on the effects of all loci, except Rht genes in our case (Bonnett et al 2022 ). Several studies have suggested the stacking of additive effects or favourable alleles of QTL from genome-wide association study as an efficient approach to improve FHB resistance and related traits (Miedaner et al 2006 ; Sidhu et al 2020 ; Ghimire et al 2022 ; Nannuru et al 2022 ). However, our results showed that despite the existence of moderate to high correlations ( r > 0.6) between the GEBV-based and stacking of additive effects (SAE) approaches, many genotypes with similar additive effects from GWAS exhibited different GEBV and FHB severity.…”

Genetic Diversity and Population Structure of Head Blight Disease Causing Fungus Fusarium graminearum in Northern Wheat Belt of India

“…In addition to India, chronic appearance of the disease has been observed in different corners of the world and major regions including China, Brazil, USA, Canada, the former USSR, Eastern and Western Europe, Romania, etc. which account for more than 50% of global production [ 10 , 11 ]. In recent reports, it has been cautioned that Fusarium head blight is liable to enhance under reduced tillage-based wheat cultivation and further aggravated with climate shift especially in the northern part of India, which is recognized as the main wheat basket of India [ 4 ].…”