Fusarium head blight (FHB) remains a serious problem due to yield loss and mycotoxin accumulation in wheat production worldwide. We previously reported that the closed‐flowering (no anther extrusion) characteristic was effective for increasing resistance to FHB infection. In this study, we investigated the relationships between the degree of anther extrusion (AE) and FHB damage using double haploid lines (DHLs), derived from F1 plants from crosses between closed‐flowering and opened‐flowering varieties. These DHLs exhibited various degrees of AE, and the degree of AE was significantly different among DHLs, regardless of the year and environment (pot‐ or field‐grown). FHB severity was the lowest in closed‐flowering DHLs, and DHLs with partially extruded anthers showed significantly higher FHB symptoms than those with closed‐flowering phenotypes. In general, DHLs with partially extruded anthers also had relatively severe FHB symptoms compared with those exhibiting full anther extrusion. FHB severity was significantly correlated with Fusarium‐damaged kernels and deoxynivalenol concentration. The results of this study showed that partially extruded anthers were considered to be a source of FHB infection. The closed‐flowering phenotype improved resistance to FHB infection. Meanwhile, phenotypes with rapid anther extrusion and ejection also could contribute to the avoidance of FHB infection.

The winter wheat variety Kitahonami shows a superior flour yield in comparison to other Japanese soft wheat varieties. To map the quantitative trait loci (QTL) associated with this trait, association mapping was performed using a panel of lines from Kitahonami’s pedigree, along with leading Japanese varieties and advanced breeding lines. Using a mixed linear model corrected for kernel types and familial relatedness, 62 marker-trait associations for flour yield were identified and classified into 21 QTLs. In eighteen of these, Kitahonami alleles showed positive effects. Pedigree analysis demonstrated that a continuous pyramiding of QTLs had occurred throughout the breeding history of Kitahonami. Linkage analyses using three sets of doubled haploid populations from crosses in which Kitahonami was used as a parent were performed, leading to the validation of five of the eight QTLs tested. Among these, QTLs on chromosomes 3B and 7A showed highly significant and consistent effects across the three populations. This study shows that pedigree-based association mapping using breeding materials can be a useful method for QTL identification at the early stages of breeding programs.

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