Title: Quantitative trait loci for resistance to Maize rayado fino virus Authors
Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 5, 2014
Publication Date: April 22, 2014
Citation: Zambrano, J.L., Jones, M.W., Francis, D.M., Tomas, A., Redinbaugh, M.G. 2014. Quantitative trait loci for resistance to Maize rayado fino virus. Molecular Breeding. DOI:10.1007/S11032-014-0091-6. Interpretive Summary: Maize 'rayado fino' or fine streak in corn can cause severe yield reductions that threaten crop production from the southern U.S. to South America. The disease is caused by a virus called Maize rayado fino virus or MRFV. Growing hybrids and cultivars that have genetic resistance to is the most economical and environmentally sustainable approach for controlling the disease in the corn crop, but genes for MRFV resistance (and markers associated with them) were not known. We mapped genes for MRFV resistance in an inbred corn line called Oh1VI that is resistant to at least ten viruses in five different virus families and in an unrelated line called K11 that is also highly virus resistant. In each line, we found a gene for MRFV resistance in the same region of chromosome 10. Identifying genes for MRFV resistance in the same position in different lines suggests that the virus resistance will be effective if it is moved into hybrids and cultivars that are used by farmers. These results are useful for maize geneticists, and for maize breeders wanting to develop virus-resistant crops.
Technical Abstract: Maize rayado fino virus (MRFV) causes one of the most important virus diseases of maize in regions of Mexico, Central and South America, where it causes moderate to severe yield losses. The virus is found from the southern United States. to northern Argentina where its vector, the maize leafhopper Dalbulus maidis, is present. Although resistance to MRFV has been identified in tropical maize lines, little was known about genes or QTL conferring resistance to MRFV. In order to identify the location of gene(s) conferring resistance to MRFV, two recombinant inbred line (RIL) mapping populations that segregated for MRFV resistance were inoculated using viruliferous leafhoppers, and their responses to virus infection were evaluated under greenhouse conditions at 7, 14 and 21 days post inoculation. A quantitative trait locus (QTL) explaining up to 23% of the total phenotypic variance was mapped on chromosome 10 in both populations, with similar genetic and physical positions identified in the two populations. The magnitude of the QTL effect and the validation in two independent populations suggests that resistance to MFRV could be transferred into elite breeding lines to develop resistant cultivars.