QTL analysis of resistance to Mal de Río Cuarto disease in maize using recombinant inbred lines

Abstract

Mal de Río Cuarto (MRC) is a devastating disease that reduces yield, quality and economic value of maize in Argentina. The objective of the present study was to map quantitative trait loci (QTL) for reactions to MRC from recombinant inbred lines (RILs). Reactions to the endemic MRC disease were evaluated in 145 advanced F 2:6 lines, derived from a cross between a resistant (BLS14) and a susceptible (Mo17) line, at four environments in the temperate semi-arid crop region of Argentina. The evaluations of disease score (SCO), disease incidence (INC) and disease severity (SEV) were carried out on each individual RIL. Low heritability estimates were found across environments for SCO (0·23), INC (0·27) and SEV (0·22). A genetic map of simple sequence repeat (SSR) markers covering a total genetic distance of 1019 cM was built. QTL for resistance to MRC disease were found on different maize chromosomes. Four significant QTL, each explaining between 0·08 and 0·14 of the total phenotypic variation, were located on chromosomes 1, 4 and 10. Two QTL specific to the INC, and one specific to SEV, may be involved in different mechanisms of resistance to MRC. Although MRC reaction is highly affected by environmental effects, the QTL × environment interaction for INC and SEV was low. Most of the QTL for reaction to MRC detected in the present study were mapped to regions of the maize genome containing genes conferring resistance to various pathogens. The significant QTL across environments are good candidates to select for MRC resistance.

Identification of significant single nucleotide polymorphisms for resistance to maize rough dwarf disease in elite maize (Zea mays L.) inbred lines

“…Among these associated SNPs, several were located in or near regions where QTLs for MRDD resistances have been mapped by linkage analysis. For (Bonamico et al 2010;Bonamico et al 2012;Di Renzo et al 2004). The SNPs of PZE-102123986 and PZE-102124518 in bin 2.06 were located near the region as QTLs for maize fine streak virus (MFSV) and maize mosaic virus (MMV) resistance in a previous study (Zambrano et al 2014).…”

Control of Virus Diseases in Maize

“…The number of genes involved in resistance and their mode of action has sometimes varied across germplasm and experiments (Bonamico et al, 2012;Louie, 1986;Pokorny & Porubova, 2006). Differential responses of resistant maize lines to different virus isolates or strains have only been documented in a few cases ( Jones, Boyd, & Redinbaugh, 2011;Jones, Redinbaugh & Louie, 2007;Louie, 1986).…”

“…Msv1, a gene that confers resistance to MSV, and QTLs that confer resistance to MRCV and MMV are found clustered on the short arm of chromosome 1 (Bonamico et al, 2012;Di Renzo et al, 2004;Kyetere et al, 1999;Welz et al, 1998;Zambrano, Jones, Brenner, et al, 2014). Msv1 and the MRCV-resistance QTLs account for almost 60% and 30% of the phenotypic variation, respectively.…”

Marker-assisted selection of <i>qMrdd8</i> to improve maize resistance to rough dwarf disease

“…Previous studies showed resistance to MRDD to be a quantitative trait (Bonamico et al 2012, Luan et al 2012, Shi et al 2012. Many QTL conferring resistance to MRDD have been identified using genomewide association studies or linkage mapping.…”