Functional markers were developed based on the critical sequence deletion of TaHRC in the Fhb1 region and validated to be diagnostic in a worldwide wheat collection. Wheat Fusarium head blight (FHB) is a devastating disease in wheat and barley worldwide. Growing FHB-resistant cultivars is an effective strategy to minimize FHB damage in wheat production. Fhb1 is a quantitative trait locus for FHB resistance with the largest effect on disease severity identified to date. With this study, we developed diagnostic DNA markers for Fhb1 by comparing the genomic sequences in Fhb1 region between near-isogenic lines contrasting in Fhb1 alleles and phenotypic effects of the markers. Two markers were developed based on a deletion mutation in an gene encoding a putative histidine-rich calcium-binding protein (TaHRC) and validated in different types of populations. Haplotype or sequence analyses of the two markers in the three sets of diversity panels demonstrated that they are diagnostic for Fhb1, and superior to all previously used markers in selection accuracy. They also have the advantages of low cost, easy assay, and are suitable for breeding programs with either high- or low-throughput marker laboratories.

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Cytoplasmic male sterility of Dian-type 1 (CMS-D1) was developed 30 years ago in Yunnan. A major gene conferring fertility restoration for the CMS-D1 system was detected by microsatellite markers in advanced inbred lines consisting of 196 maintainers and 62 restorers developed in breeding programmes of hybrid rice involving the CMS-D1 system. The gene was mapped between two simple sequence repeat markers, OSR33 and RM228, on chromosome 10, and was temporarily designated as Rf-D1(t). The genetic distances of the gene to the two microsatellite markers were 3.4 and 5.0 cM, respectively. This linkage was confirmed by using an F 2 population derived from a cross between a CMS-D1 line and a restorer. This study also demonstrated that using OSR33 was reliable and efficient for identification of restoring lines in hybrid rice breeding with the CMS-D1 system.