Location: Hard Winter Wheat Genetics ResearchTitle: A novel QTL associated with dwarf bunt resistance in Idaho 444 winter wheat
|Chen, Janli - University Of Idaho|
|Zhang, Junli - University Of California|
|Hole, David - Utah State University|
|Souza, Edward - Bayer Cropscience|
Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/2016
Publication Date: 9/28/2016
Publication URL: http://handle.nal.usda.gov/10113/5510075
Citation: Chen, J., Guttieri, M.J., Zhang, J., Hole, D., Souza, E., Goates, B. 2016. A novel QTL associated with dwarf bunt resistance in Idaho 444 winter wheat. Journal of Theoretical and Applied Genetics. 129(12):2313-2322. doi:10.1007/s00122-016-2783-2.
Interpretive Summary: Dwarf bunt is a problematic disease of winter wheat grown in regions with prolonged snow cover because the pathogen produces sori, known as bunt balls, that replace the grain with inedible, foul-smelling spores. Excellent host plant resistance sources are available to breeders, but field selection can only be conducted under very specific environmental conditions. Therefore molecular markers for host plant resistance are essential tools for selection. Using a population of lines derived from a cross between a highly dwarf-bunt susceptible genotype, 'Rio Blanco,' and a highly dwarf bunt-resistant genotype, 'Idaho 444', a very strong and highly repeatable association between a molecular marker on the short arm of chromosome 7D and dwarf bunt resistance was identified. The original molecular marker has been converted into a breeder-friendly marker for use in selection. This marker will facilitate the incorporation of this valuable resistance into global winter wheat germplasm.
Technical Abstract: A significant component of Mendel’s legacy has been the ability to discover, map, and utilize genes for resistance to diseases in the crops that the world relies on for food. Dwarf bunt [Tilletia contraversa Kühn (syn. Tilletia controversa)] is a destructive disease of wheat (Triticum aestivum L.) that reduces grain yield and quality. A number of genes conferring resistance to dwarf bunt have been used by breeding programs for nearly one hundred years. However, few markers were identified that can be used in selection of dwarf bunt resistance. A recombinant inbred line (RIL) population derived from the bunt resistant germplasm, Idaho 444 (IDO444) and the susceptible cultivar, Rio Blanco, was evaluated for phenotypic reaction to dwarf bunt inoculation in four trials in two locations over three years. The population was genotyped with the Diversity Arrays Technology (DArT) and the Illumina Infinium 9K iSelect marker platforms. A total of three QTL were detected, and all resistant alleles were from IDO444. QTL Q.DB.ui-7DS on 7DS was determined based on the location of a DArT marker wPt-2655 (X116197), which was consistently detected and explained 32 to 56% of phenotypic variation among the four trials. QTL Q.DB.ui-1A on 1A was detected in three USU trials and explained 11-15% of phenotypic variation. QTL Q.DB.ui-2B on 2B was detected in two USU and one USDA trials and explained up to 6% of phenotypic variation. Two PCR-based markers were developed based on the sequence of wPt-2655 and validated in the RIL population and dwarf bunt differential lines.