FIRST REPORT OF GENOMIC REGIONS ASSOCIATED TO MULTIPLE DISEASE RESISTANCE IN ARGENTINEAN MAIZE GERMPLASM

KISTNER, MARÍA BELÉN; MONTENEGRO, LUCÍA DANIELA; BARICALLA, A; PERDOMO, S; CERVIGNI, GERARDO DOMINGO LUCIO; GALDEANO, E; IGLESIAS, JULIANA

Congreso; 5º Congreso Argentino de Fitopatología: 59º Reunión APS División Caribe; 2021

Asociación Argentina de Fitopatólogos

Multiple disease resistance (MDR), i.e. a host plant resistant to more than one disease, is a desirable trait for plant breeders; however, little is known about their genetic control in maize. Therefore, the identification of candidate genomic regions and genes controlling MDR is of great interest. The Argentine public temperate inbred maize collection at INTA Pergamino has a long history of selection in environments with multiple pathogen pressures. Thus regions/genes controlling MDR are expected to be present in the panel of genotypes. In this study, we aimed to identify these regions through a genome-wide association study (GWAS). We collected phenotypic information of 87 maize tempered inbred lines based on their performance for three ear diseases and four foliar diseases evaluated in up to five environments. For each disease, GWAS was performed on the best linear unbiased estimators (BLUEs) obtained from the multi-environment trial analysis, fitting a mixed model that accounts for both, population structure and family relatedness. Physical position of significant markers was compared across diseases. Three genomic regions for MDR were identified: two regions in chromosome 2 for resistance to ear diseases (Fusarium ear rot, Gibberella ear rot and/or common smut), and one region in chromosome 3 for resistance to foliar diseases (bacterial leaf streak and southern corn leaf blight). Candidate genes involved in disease resistance at these loci were examined based on known functions, homology, and expression pattern.