QTL mapping for resistance to ear rot caused by Fusarium graminearum using an IBM Syn10 DH population in maize

Gibberella ear rot (GER) caused by Fusarium graminearum (teleomorph Gibberella zeae), is one of the most devastating diseases in maize that not only severely reduces grain yield but also contaminates the kernels with potent mycotoxins which is harmful to livestock and humans. Identification of stable quantitative trait loci (QTL) and candidate genes conferring resistance is a promising strategy in resistance breeding programs for the disease. Here, the ten times intermated B73 × Mo17-doubled haploid (IBM Syn10 DH) population comprising a total of 298 diverse maize inbred lines were subjected to phenotypic evaluation in a 2-year field test across two environments, and the IBM Syn10 DH population were employed to detect QTL across multiple environments using an ultra-high-density bin map. Ten QTL were detected on chromosomes 1, 2, 3, 6, 7, 8, and 9, respectively. Of them, a major QTL on chromosome 7, named qGRfg7, could explain 33.26% of the phenotypic variation. Based on fine-mapping strategy, we narrowed down the interested region into 91 kb, flanked by two developed Indel markers. A predicted gene in the mapped region, encoding a lipopolysaccharide-binding protein (LBP), is suggested to be a candidate gene conferring resistance to GER disease. These results will facilitate the breeding process for GER resistance by marker-assisted selection (MAS) in maize.