Resumo

DI RENZO, M.A  e  BONAMICO, N.C. Mapeo de QTL para resistencia a mal de río cuarto de maíz. BAG, J. basic appl. genet. [online]. 2013, vol.24, n.1, pp.13-18. ISSN 1852-6233.

Mal de Río Cuarto (MRC) is the most important disease of maize. It is endemic in certain areas of Argentina, and produced by a vector identified as Mal de Río Cuarto virus (MRCV), genus Fijivirus, Family Reoviridae. Initial studies showed that resistance to MRCV is an oligogenic trait with moderate to low heritability, governed by nuclear genes with dominant and additive effects. Genotypes usually have unpredictable responses because this viral disease, which occurs unsystematically, has a marked genotype-environment interaction. QTL mapping for MRCV reaction allowed the determination of number and individual effects of the loci involved and the estimation of interactions among these genes and with the environment. Results obtained with different mapping populations, genetic backgrounds and methods of statistical analysis indicate that QTLs are located in the same regions where loci of resistance to other pathogens are grouped into clusters. QTLs for reaction to MRCV are located in chromosomes 1, 3, 4, 6, 8, and 10, and account for 6-42 % of the phenotypic variation depending on populations, environments and methods of analysis. In particular, QTLs of bins 1.02/3, 8.02/3 and 10.02/4 could be considered promising for detecting candidate genes related to this viral disease. Additional studies will allow their use in breeding, germplasm conservation and genomic analysis.

Palavras-chave : Molecular markers; Quantitative trait loci; Viral disease; MRCV.

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