Linkage of Molecular Markers to Cercospora zeae-maydis Resistance in Maize
- Stuart G. Gordona,
- Michael Bartschc,
- Inge Matthiesc,
- Hans O. Geversd,
- Patrick E. Lippsb and
- Richard C. Pratt *a
- a Department of Horticulture and Crop Science, The Ohio State University/Ohio Agricultural Research & Development Center, 1680 Madison Ave., Wooster, OH 44691
c University of Hohenheim, 350 Institute of Plant Breeding, Seed Science, and Population Genetics, 70593 Stuttgart, Germany
d Quality Seed CC, P.O. Box 100881, Scottsville 3209, KZN, Republic of South Africa
b Department of Plant Pathology, The Ohio State University/OARDC, 1680 Madison Ave., Wooster, OH 44691
Gray leaf spot (GLS) of maize (Zea mays L.) caused by Cercospora zeae-maydis Tehon & E.Y. Daniels, can greatly reduce grain yield in conducive environments worldwide. This study was undertaken to evaluate a novel source of resistance to C. zeae-maydis across macroenvironments and link molecular markers to resistance loci by selective genotyping. A population of 144 F2:3 progeny lines derived from a cross between resistant maize inbred VO613Y and susceptible inbred Pa405 were evaluated at Wooster, OH, USA, and Cedara Agricultural Research Institute, Department of Agriculture, KZN, Republic of South Africa (RSA), for resistance to C. zeae-maydis The lines were assigned to phenotypic classes (resistant, intermediate, and susceptible) on the basis of percent leaf area affected (PLAA) values across environments. F2:4 progeny lines were produced by controlled self-pollination of an individual plant within each F2:3 line. F2:4 lines derived from resistant and susceptible classes were evaluated at two Ohio locations. The same lines, plus a random sample of 54 F2:4 lines representing the intermediate class, were evaluated at Cedara. Molecular marker data were analyzed on the basis of PLAA means of F2:4 progenies by Kruskal–Wallis analysis and several markers on chromosomes 2 and 4 were deemed to be significantly associated with resistance. Additional molecular markers were added and composite interval mapping was conducted on genetic maps of those chromosomes. Quantitative trait loci (QTL) located on chromosome arms 2L and 4L together explained 40 to 47% of the phenotypic variation. A resistance gene analog probe flanked the significant interval on chromosome 4L. These intervals on chromosomes 2L and 4L were detected in all tests and we consider them to be suitable candidate QTL for marker-assisted selection (MAS). These results indicate that VO613Y is a source of resistance with potential to be deployed effectively in both southern Africa and the U.S. Corn Belt.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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