Identification of quantitative trait loci controlling resistance to gray leaf spot disease in maize

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.

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Quantitative trait loci associated with resistance to gray leaf spot and grain yield in corn

Ciência e Agrotecnologia ◽

10.1590/s1413-70542012000100004 ◽

2012 ◽

Vol 36 (1) ◽

pp. 31-38 ◽

Cited By ~ 5

Author(s):

Adriano Delly Veiga ◽

Renzo Garcia Von Pinho ◽

Luciane Vilela Resende ◽

Édila Vilela de Resende Von Pinho ◽

Márcio Balestre ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Grain Yield ◽

Quantitative Trait ◽

Leaf Spot ◽

Genetic Resistance ◽

Gray Leaf Spot ◽

Single Marker Analysis ◽

F1 Hybrid ◽

F2 Population ◽

Trait Loci

The main objectives of hybrid development programs include incorporating genetic resistance to diseases and increasing grain yield. Identification of Quantitative Trait Loci (QTL) through the statistical analysis of molecular markers allows efficient selection of resistant and productive hybrids. The objective of this research was to identify QTL associated with resistance to gray leaf spot and for grain yield in the germplasm of tropical corn. We used two strains with different degrees of reaction to the disease; the genotypes are owned by GENESEEDS Ltda, their F1 hybrid and the F2 population. The plants were evaluated for gray leaf spot resistance, for grain yield and were genotyped with 94 microsatellite markers. Association of the markers with the QTL was performed by single marker analysis using linear regression and maximum likelihood analysis. It was observed that the additive effect was predominant for genetic control of resistance to gray leaf spot, and the dominant effect in that of grain yield. The most promising markers to be used in studies of assisted selection are: umc2082 in bins 4.03 and umc1117 in bins 4.04 for resistance to gray leaf spot; for grain yield umc1042 in bins 2.07 and umc1058 in bins 4.11.

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Quantitative Trait Loci Associated with Gray Leaf Spot Resistance in St. Augustinegrass

Plant Disease ◽

10.1094/pdis-04-20-0905-re ◽

2020 ◽

Vol 104 (11) ◽

pp. 2799-2806

Author(s):

Xingwang Yu ◽

Steve E. Mulkey ◽

Maria C. Zuleta ◽

Consuelo Arellano ◽

Bangya Ma ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Leaf Spot ◽

Magnaporthe Grisea ◽

Disease Incidence ◽

Snp Markers ◽

Gray Leaf Spot ◽

Linkage Groups ◽

Resistant Parent ◽

Trait Loci

Gray leaf spot (GLS), caused by Magnaporthe grisea, is a major fungal disease of St. Augustinegrass (Stenotaphrum secundatum), causing widespread blighting of the foliage under warm, humid conditions. To identify quantitative trait loci (QTL) controlling GLS resistance, an F1 mapping population consisting of 153 hybrids was developed from crosses between cultivar Raleigh (susceptible parent) and plant introduction PI 410353 (resistant parent). Single-nucleotide polymorphism (SNP) markers generated from genotyping-by-sequencing constituted nine linkage groups for each parental linkage map. The Raleigh map consisted of 2,257 SNP markers and spanned 916.63 centimorgans (cM), while the PI 410353 map comprised 511 SNP markers and covered 804.27 cM. GLS resistance was evaluated under controlled environmental conditions with measurements of final disease incidence and lesion length. Additionally, two derived traits, area under the disease progress curve and area under the lesion expansion curve, were calculated for QTL analysis. Twenty QTL were identified as being associated with these GLS resistance traits, which explained 7.6 to 37.2% of the total phenotypic variation. Three potential GLS QTL “hotspots” were identified on two linkage groups: P2 (106.26 to 110.36 cM and 113.15 to 116.67 cM) and P5 (17.74 to 19.28 cM). The two major effect QTL glsp2.3 and glsp5.2 together reduced 20.2% of disease incidence in this study. Sequence analysis showed that two candidate genes encoding β-1,3-glucanases were found in the intervals of two QTL, which might function in GLS resistance response. These QTL and linked markers can be potentially used to assist the transfer of GLS resistance genes to elite St. Augustinegrass breeding lines.

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Validation of Consensus Quantitative Trait Loci Associated with Resistance to Multiple Foliar Pathogens of Maize

Phytopathology ◽

10.1094/phyto-99-5-0540 ◽

2009 ◽

Vol 99 (5) ◽

pp. 540-547 ◽

Cited By ~ 14

Author(s):

Godfrey Asea ◽

Bindiganavile S. Vivek ◽

George Bigirwa ◽

Patrick E. Lipps ◽

Richard C. Pratt

Keyword(s):

Quantitative Trait Loci ◽

Disease Severity ◽

Quantitative Trait ◽

Gray Leaf Spot ◽

Sub Saharan Africa ◽

Maize Production ◽

Resistant Parent ◽

Trait Loci ◽

Sub Saharan ◽

Corn Leaf Blight

Maize production in sub-Saharan Africa incurs serious losses to epiphytotics of foliar diseases. Quantitative trait loci conditioning partial resistance (rQTL) to infection by causal agents of gray leaf spot (GLS), northern corn leaf blight (NCLB), and maize streak have been reported. Our objectives were to identify simple-sequence repeat (SSR) molecular markers linked to consensus rQTL and one recently identified rQTL associated with GLS, and to determine their suitability as tools for selection of improved host resistance. We conducted evaluations of disease severity phenotypes in separate field nurseries, each containing 410 F2:3 families derived from a cross between maize inbred CML202 (NCLB and maize streak resistant) and VP31 (a GLS-resistant breeding line) that possess complimentary rQTL. F2:3 families were selected for resistance based on genotypic (SSR marker), phenotypic, or combined data and the selected F3:4 families were reevaluated. Phenotypic values associated with SSR markers for consensus rQTL in bins 4.08 for GLS, 5.04 for NCLB, and 1.04 for maize streak significantly reduced disease severity in both generations based on single-factor analysis of variance and marker-interval analysis. These results were consistent with the presence of homozygous resistant parent alleles, except in bin 8.06, where markers were contributed by the NCLB-susceptible parent. Only one marker associated with resistance could be confirmed in bins 2.09 (GLS) and 3.06 (NCLB), illustrating the need for more robust rQTL discovery, fine-mapping, and validation prior to undertaking marker-based selection.

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