Quantitative trait loci for resistance to Maize rayado fino virus

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 USA 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 quantitative trait locus (QTL) conferring resistance to MRFV. In order to identify the location of genes conferring resistance to MRFV, two recombinant inbred line mapping populations that segregated for MRFV resistance were inoculated using viruliferous leafhoppers, and their responses to virus inoculation were evaluated under greenhouse conditions 7, 14 and 21 days post inoculation. A 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.