Association mapping of leaf rust resistance loci in a spring wheat core collection.
We identified 15 potentially novel loci in addition to previously characterized leaf rust resistance genes from 1032 spring wheat accessions. Targeted AM subset panels were instrumental in revealing interesting loci. Leaf rust is a common disease of wheat, consistently reducing yields in many wheat-growing regions of the world. Although fungicides are commonly applied to wheat in the United States (US), genetic resistance can provide less expensive, yet effective control of the disease. Our objectives were to map leaf rust resistance genes in a large core collection of spring wheat accessions selected from the United States Department of Agriculture-Agricultural Research Service National Small Grains Collection (NSGC), determine whether previously characterized race-nonspecific resistance genes could be identified with our panel, and evaluate the use of targeted panels to identify seedling and adult plant resistance (APR) genes. Association mapping (AM) detected five potentially novel leaf rust resistance loci on chromosomes 2BL, 4AS, and 5DL at the seedling stage, and 2DL and 7AS that conditioned both seedling and adult plant resistance. In addition, ten potentially novel race-nonspecific resistance loci conditioned field resistance and lacked seedling resistance. Analyses of targeted subsets of the accessions identified additional loci not associated with resistance in the complete core panel. Using molecular markers, we also confirmed the presence and effectiveness of the race-nonspecific genes Lr34, Lr46, and Lr67 in our panel. Although most of the accessions in this study were susceptible to leaf rust in field and seedling tests, many resistance loci were identified with AM. Through the use of targeted subset panels, more loci were identified than in the larger core panels alone.
Department of Agronomy and Plant Genetics, University of Minnesota, St Paul, MN, USA.|The Land Institute, Salina, KS, USA.
M Kathryn
MK
Turner
USDA-ARS, Cereal Disease Laboratory, University of Minnesota, St Paul, MN, USA.|Department of Plant Pathology, University of Minnesota, St Paul, MN, USA.
James A
JA
Kolmer
Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA.
Michael O
MO
Pumphrey
Department of Crop and Soil Sciences, Washington State University, Pullman, WA, USA.
Peter
P
Bulli
USDA ARS Genotyping Laboratory, Biosciences Research Laboratory, Fargo, ND, USA.
Shiaoman
S
Chao
Department of Agronomy and Plant Genetics, University of Minnesota, St Paul, MN, USA. ander319@umn.edu.
James A
JA
Anderson
D001487:Basidiomycota; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D056426:Genetic Loci; D005819:Genetic Markers; D060005:Genotyping Techniques; D016014:Linear Models; D015810:Linkage Disequilibrium; D008957:Models, Genetic; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D014908:Triticum / Q000235:genetics* / Q000382:microbiology
D005819:Genetic Markers