Genetic analysis of ergot resistance in a Canada Western Red Spring Wheat population

The fungal pathogen Claviceps purpurea (Fr.) Tul. infects wheat ovaries during flowering causing ergot disease. The disease is significant because toxic alkaloids present in ergot sclerotia are harmful to the circulatory system and neurotransmission of both humans and animals when infested grain is consumed. Few sources of resistance to C. purpurea have been reported in wheat and no specific resistance genes have been identified. We grew in the field near Swift Current, Canada over multiple years a doubled haploid hard red spring wheat population of 774 lines from a cross of ‘Carberry’ by ‘AC Cadillac’ and evaluated natural ergot infection. Genotyping was done with the Infinium II iSelect 90K wheat assay and 6806 single nucleotide polymorphisms were mapped. Composite interval mapping detected seven quantitative trait loci (QTL). ‘Carberry’ contributed resistance alleles for QTL on chromosomes 2B, 5A and 6A while QTL on chromosomes 2A, 3D2, 6B and 7B were contributed by ‘AC Cadillac’. The expression of the 2B, 5A and 6B QTL was more stable as they were detected in more than one environment. Among the seven QTL, the 7B QTL explained the least phenotypic variation of 1.3%, while the QTL on chromosome 6B accounted for the most phenotypic variation at 4.4%. This information will be valuable in marker-assisted breeding for ergot resistance in hexaploid wheat.