title: Identification and mapping in spring wheat of genetic factors controlling stem rust resistance and the study of their epistatic interactions across multiple environments.
abstract: Stem rust (Puccinia graminis f. sp. tritici) is responsible for major production losses in hexaploid wheat (Triticum aestivum L.) around the world. The spread of stem rust race Ug99 and variants is a threat to worldwide wheat production and efforts are ongoing to identify and incorporate resistance. The objectives of this research were to identify quantitative trait loci (QTL) and to study their epistatic interactions for stem rust resistance in a population derived from the Canadian wheat cultivars AC Cadillac and Carberry. A doubled haploid (DH) population was developed and genotyped with DArT(®) and SSR markers. The parents and DH lines were phenotyped for stem rust severity and infection response to Ug99 and variant races in 2009, 2010 and 2011 in field rust nurseries near Njoro, Kenya, and to North American races in 2011 and 2012 near Swift Current, SK, Canada. Seedling infection type to race TTKSK was assessed in a bio-containment facility in 2009 and 2012 near Morden, MB. Eight QTL for stem rust resistance and three QTL for pseudo-black chaff on nine wheat chromosomes were identified. The phenotypic variance (PV) explained by the stem rust resistance QTL ranged from 2.4 to 48.8 %. AC Cadillac contributed stem rust resistance QTL on chromosomes 2B, 3B, 5B, 6D, 7B and 7D. Carberry contributed resistance QTL on 4B and 5A. Epistatic interactions were observed between loci on 4B and 5B, 4B and 7B, 6D and 3B, 6D and 5B, and 6D and 7B. The stem rust resistance locus on 6D interacted synergistically with 5B to improve the disease resistance through both crossover and non-crossover interactions depending on the environment. Results from this study will assist in planning breeding for stem rust resistance by maximizing QTL main effects and epistatic interactions.
authors: Semiarid Prairie Agricultural Research Center, Agriculture and Agri-Food Canada, Swift Current, SK, Canada. dr.artisingh@yahoo.com
authors: A
authors: A
authors: Singh
authors: R E
authors: RE
authors: Knox
authors: R M
authors: RM
authors: DePauw
authors: A K
authors: AK
authors: Singh
authors: R D
authors: RD
authors: Cuthbert
authors: H L
authors: HL
authors: Campbell
authors: D
authors: D
authors: Singh
authors: S
authors: S
authors: Bhavani
authors: T
authors: T
authors: Fetch
authors: F
authors: F
authors: Clarke
mesh_terms: D001487:Basidiomycota; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D060467:Disease Resistance / Q000235:genetics*; D002523:Edible Grain / Q000235:genetics; D004843:Epistasis, Genetic; D005838:Genotype; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018547:Plant Stems; D040641:Quantitative Trait Loci / Q000235:genetics*; D014908:Triticum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
references: Theor Appl Genet. 2011 Jan;122(1):143-9
references: 20725713
references: Theor Appl Genet. 2011 Dec;123(8):1257-68
references: 21811818
references: Theor Appl Genet. 2012 Aug;125(4):749-58
references: 22534791
references: Plant Dis. 2012 Apr;96(4):590
references: 30727416
references: Mol Breed. 2013 Feb;31(2):405-418
references: 23396999
references: Plant Dis. 2013 Apr;97(4):557
references: 30722237
references: Bioinformatics. 2008 Mar 1;24(5):721-3
references: 18202029
references: Plant Dis. 2000 Feb;84(2):203
references: 30841334
references: Annu Rev Phytopathol. 2011;49:465-81
references: 21568701
references: Plant Dis. 2008 Jun;92(6):923-926
references: 30769714
references: Genetics. 2007 Nov;177(3):1889-913
references: 17947425
references: Plant Dis. 2009 Apr;93(4):367-370
references: 30764215