Genomic regions conferring partial Fusarium crown rot resistance in commercial wheat cultivars

Abstract

This study aimed to genetically characterize Fusarium crown rot (FCR) resistance in high-yielding commercial spring bread wheat (Triticum aestivum L.) cultivars SST 087, with partial FCR resistance, and susceptible cultivar PAN 3471. Multi-year trials were conducted in South Africa, and one trial was run in Australia. Nine FCR quantitative trait loci (QTLs) were identified across eight different chromosomes (1A, 1D, 2A, 2B, 3D, 5B, 6D, 7A, and 7D). A QTL on chromosome 7A had the highest logarithm of the odds (LOD) score of 7.8 with 15% of the phenotypic variance explained and was identified across multiple years and in both the South African and Australian environments. The 35K Affymetrix Axiom Wheat Breeders’ Array data were used to identify sequence data for QFcr.cg-7A for development of FCR markers for marker-assisted selection in wheat breeding programs. QTLs associated with grain yield under FCR infection were identified on chromosomes 2A, 3D, 5B, 5DS, and 7A, with the QTL on 5B having the highest LOD score (4.6). A yield QTL on the distal end of chromosome 2AS was detected in the chromosome region where the Aegilops ventricosa Tausch 2N^VS translocation-associated markers map. The yield benefit was associated with the absence of this translocation in PAN 3471 in 2019, which was a drought stressed year with a much lower rainfall compared to 2020, when it went undetected. We have identified partial FCR resistance in the high-yielding commercial cultivar SST 087 and have identified FCR markers for marker-assisted selection in wheat breeding programs.