Mapping quantitative trait loci for Fusarium head blight resistance in the U.S. winter wheat

Abstract

Fusarium head blight (FHB) is one of the devastating wheat diseases worldwide. It reduces not only yield, but also grain quality due to mycotoxins produced by the pathogen Fusarium graminearum. To identify consistent quantitative trait loci (QTLs) for FHB resistance in two US winter wheat ‘CI13227’ and ‘Lyman’, we genotyped a double haploid (DH) population from ‘’ x ’CI13227’ X ‘Lakin’ using Illumina wheat 90K single nucleotide polymorphism (SNP) chips and two recombinant inbred line (RIL) populations from ‘Lyman’x ’Overley’ and ‘Lyman’x ’CI13227’ using genotyping-by-sequencing (GBS) and evaluated the three populations for FHB type II resistance in greenhouse and field experiments. QTL mapping identified four QTLs on chromosomes 4BS, 5AL, 2DS and 7A in the ‘CI13227’ x ‘Lakin’ population, which explained 8-17% of the phenotypic variation in different experiments. The QTL on 4BS from CI13227 showed the largest effect among QTLs detected in the ‘CI13227’ x ‘Lakin’ population and were consistently detected in three experiments. ‘CI13227’ contributed the resistance alleles at QTLs on 2DS and 7A, whereas ‘Lakin’ contributed the resistance allele at 5AL QTL. The 7A QTL was detected in only one experiment. The QTLs on the chromosomes 4B and 2D showed a high correlation with plant height, suggesting a linked genes or pleiotropic effect of these QTLs. In the ‘Lyman’/’Overley’ population, six QTLs were located on the chromosomes 1A, 2A, 3A, 1B, 2B and 4B, and explained 5.5 -21% of the phenotypic variations for type II resistance. The QTL on 3A from ‘Lyman’ showed the largest effects and detected in two greenhouses experiments. Significant correlation was not detected between the PSS and plant height in this population. In the ‘Lyman’/’CI13227’ population, four QTLs were detected with two QTLs on chromosomes 1A and 7A from ‘CI13227’ and chromosomes 2B and 3A from ‘Lyman’ and QTLs on 7A from ‘CI13227’ and 2B and 3A from ‘Lyman’ confirmed the results from the previous two populations. Markers for the repeatable QTLs were converted into Kompetitive allele specific PCR (KASP) markers for marker-assisted breeding to pyramid these QTLs in U.S. winter wheat.