Quantitative Trait Loci Associated with Resistance to Gray Leaf Spot of Corn

Abstract

The susceptible parent FR1141, the resistant parent 061, the F1 cross, and 301 families selfed once from backcrosses to the susceptible parent were evaluated for gray leaf spot (GLS) severity for two years in Urbana, IL, and one year in Andrews, NC. Linkage between ear height and GLS severity was suspected. Therefore, plant height characteristics were noted for two years in Urbana, IL. Eighty-six polymorphic probes were used to construct a random fragment length polymorphism linkage map, and the presence, locations, effects, and interactions of quantitative trait loci (QTL) associated with GLS, plant and ear height were determined. Five QTL were significantly associated with GLS resistance across all environments and rating periods. These five regions are associated with additive effects on phenotype and account for between 51.0 and 58.7% of the phenotypic variation associated with GLS severity. Additionally, six QTL were identified with maturity-dependent associations to GLS severity. Heritability of GLS resistance was estimated to be approximately 0.73. Four QTL were identified with associations to ear height relative to total plant height. One of the four was associated with higher ear height and GLS resistance.

Multivariate analysis of maize disease resistances suggests a pleiotropic genetic basis and implicates a GST gene

“…Finally, the map position of the GST gene identified in this study colocalized with or immediately flanked quantitative trait loci for SLB, GLS, and NLB identified in previous studies [compare position 298 cM on chromosome 7 with quantitative trait loci (4)]. A closer examination suggested that these resistance loci were not attributable to the effect of this GST gene; based on our SNP data, each of the significantly associated GST SNPs identified in this study (above and below) was invariant among the five biparental population parents used in previous studies (33)(34)(35)(36)(37)(38). Alternatively, other GST alleles that are undetectable in our study could underlie functional variation at these quantitative trait loci.…”

Precise Mapping of Quantitative Trait Loci for Resistance to Southern Leaf Blight, Caused by Cochliobolus heterostrophus Race O, and Flowering Time Using Advanced Intercross Maize Lines

“…Several mapping studies have examined both maturityrelated and disease-related traits for maize necrotrophic diseases in the same populations (Bubeck et al 1993;Jung et al 1994;Jiang et al 1999;Clements et al 2000;Carson et al 2004;. While none showed a strong correlation between the two traits, colocalization of disease QTL and maturity-related QTL and/or significant correlations between disease resistance and time to anthesis were observed in some of these studies, especially for studies on gray leaf spot-resistance QTL.…”

Infection process in resistant and susceptible maize (Zea mays L.) genotypes to Cercospora zeae-maydis (type II)

“…Quantitative resistance to grey leaf spot leads to prolonged latent and incubation periods, reduced infection rates, sporulation capacity and the number of lesions (Beckman & Payne 1982;Carson & Goodman 2006). The resistance factors have been mapped to three different chromosomes at least, with some of the quantitative trait loci (QTL) consistently expressed across environments (Clements et al 2000;Gordon et al 2004). Carson and Goodman (2006) reported that resistance to grey leaf spot in maize appears to be equally effective against both type I and type II of C. zeae-maydis and that aggressive isolates, regardless of which sibling species of C. zeae-maydis, should be used to select for grey leaf spot resistance in field trials.…”