Fhb9, a major QTL for Fusarium head blight resistance improvement in wheat

Abstract

head blight (FHB), mainly caused by , is one of the most devastating diseases of wheat worldwide. Identification and validation of major quantitative trait loci (QTLs) for FHB resistance without negative effects on agronomic traits is critical to success in breeding FHB-resistant cultivars. In this study, a stable major QTL on chromosome arm 2DL was identified by evaluating a recombinant inbred line (RIL) population derived from Shi4185×Shijiazhuang 8 in both field and greenhouse experiments. QTL mapping and pedigree analyses indicated that the 2DL QTL is the same QTL as previously identified in Ji5265, therefore, designated . Four kompetitive amplicon sequence polymorphism (KASP) markers were developed based on exome capture sequencing data to enhance marker density in the region, and it was delimited to an interval between single nucleotide polymorphism (SNP) markers (533.8) and (525.9 Mb) explained 26.0-30.1% of the phenotypic variation. Analysis of the geographic distribution of the resistance allele suggested that it originated from Huang-Huai winter wheat region in China, and very low frequency of in modern Chinese cultivars reveals that it has not been widely deployed in breeding programs. Field and greenhouse evaluation of yield-related traits of near-isogenic lines (NILs) contrasting in alleles indicated that resistance allele did not show any adverse effects on those traits. showed an additive effect on enhancing FHB resistance with . Therefore, is a valuable major QTL for improving FHB resistance in wheat and the near-diagnostic markers developed in this study will facilitate its deployment in wheat breeding programs.