Meta-analysis of QTL studies for resistance to fungi and viruses in maize

ROSSI, E.; RUIZ, M.; RUEDA CALDERÓN, A.; BRUNO, C.; BONAMICO, N.; BALZARINI, M.

Congreso; XXII International Congress of Genetics; 2018

Several studies report quantitative trait loci (QTL) for disease resistance. Discovering communalities among them is crucial. First, we performed a systematic review (SR) by searching multiple databases with the term ("Zea mays" or maize or corn), ((resistance or tolerance) and "disease"), (QTL or loci or "Quantitative Trait Loci"). Several studies on QTL for resistance to fungi and viruses resistance were found, but few reported bacteria resistance. Second, we performed a meta-analysis (MA) aimed at identifying maize chromosomes carrying major-effect QTL for resistance to diseases caused by fungi and viruses. Overall, 110 primary studies with data on genetic effects of fungal and viral resistance reported 1,080 QTL. For each chromosome, reported QTL were counted, and a global odd ratio of carrying major effect loci was calculated by averaging findings across studies. Although the greatest number of QTL was reported in chromosome 1, 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 loci in the rest of the genome. Other chromosomes also have high odds of significant QTL (chromosomes 6, 5, 1 and 2), but the major-effect QTL reported for resistance to fungal diseases were not located on the same chromosomes as those with virus resistance. There was no agreement among studies in the occurrence of major-effect loci on chromosome 3. Our results summarize published findings and strengthen information about key genome regions for maize breeding against yield losses caused by fungi and viruses.