Identifying inbred lines with resistance to endemic diseases in exotic maize germplasm

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

CROP SCIENCE

CROP SCIENCE SOC AMER

Lugar: Baltimore; Año: 2020 vol. 60 p. 3141 - 3150

0011-183X

Mal de Rio Cuarto (MRC) and common rust (CR), caused by Mal de Rio Cuartovirus (MRCV) and Puccinia sorghi, respectively, are endemic diseases affectingmaize (Zea mays L.) production in Argentina. Exotic maize germplasm is animportant source of resistance to these diseases. The aim of this work was toidentify maize lines that exhibit MRC and CR resistance. A multienvironmenttrial was performed to phenotypically assess a diverse panel of inbred lines fromthe InternationalMaize andWheat Improvement Center (CIMMYT). The maizelines were evaluated using a disease severity index (DSI) for MRC and CR inthe central area of Argentina. A multitrait mixed linear model (MLM) was usedto identify the lines with the best performance for both diseases and estimategenetic parameters.No correlation of resistance betweenMRCandCRwas foundamong the tested lines. Additionally, best linear unbiased predictions (BLUPs) ofgenotypic effects were used as response variable to perform a genome-wide associationstudy (GWAS). The GWAS revealed promising alleles for maize breeding,two associated with MRC and three with CR. Lines with lower DSI forMRC andCR were identified as novel materials for incorporating resistance to the localgermplasm.