Meta-Analysis of QTL Studies for Resistance to Fungi and Viruses in Maize

Several studies reported quantitative trait loci (QTL) for disease resistance. Discovering communalities among them is crucial. First, we performed a literature systematic review to search published QTL for maize (Zea mays L.) disease resistance. A total of 110 studies containing QTL information related to fungi and virus resistance were found, but few reported QTL for bacteria resistance. Second, we performed a meta-analysis aimed at identifying genomic regions carrying major-effect QTL for resistance to fungal and viral diseases. Results show that the greatest number of QTL was reported in chromosome 1, but the odds of finding major-effect loci for fungus and virus resistance in chromosome 10 were twice as high as the odds of finding those main loci in the rest of the genome. Bins 1.03, 1.04, 1.05, 1.06, 1.10, 2.04, 2.07, 5.03, 6.02, and 10.06 in chromosomes 1, 2, 5, 6, and 10 were recognized as genomic regions where major-effect QTL are located. The major-effect QTL reported for resistance to fungal diseases were not located on the same chromosomes as those with virus resistance, except for chromosome 10. There was no agreement among studies in the occurrence of major-effect loci on chromosomes 3 and 8. Our results summarize and confirm published findings about key genomic regions for maize molecular breeding against diseases that can cause significant yield losses.