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Identification of quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in multiple assay environments in the Pacific Northwestern US.

Poole GJ, Smiley RW, Paulitz TC, Walker CA, Carter AH, See DR, Garland-Campbell K - Theor. Appl. Genet. (2012)

Bottom Line: The most significant and consistent QTL across screening environments was located on chromosome 3BL, inherited from the PNW cultivars Macon and Otis, with maximum LOD scores of 22 and 9 explaining 36 and 23% of the variation, respectively for the Sunco/Macon and Sunco/Otis populations.The SSR markers Xgwm247 and Xgwm299 flank these QTL and are being validated for use in marker-assisted selection for FCR resistance.This is the first report of QTL associated with FCR resistance in the US.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop and Soil Sciences, Washington State University, P.O. Box 6420, Pullman, WA 99164-6420, USA. Grant.Poole@sa.gov.au

ABSTRACT
Fusarium crown rot (FCR), caused by Fusarium pseudograminearum and F. culmorum, reduces wheat (Triticum aestivum L.) yields in the Pacific Northwest (PNW) of the US by as much as 35%. Resistance to FCR has not yet been discovered in currently grown PNW wheat cultivars. Several significant quantitative trait loci (QTL) for FCR resistance have been documented on chromosomes 1A, 1D, 2B, 3B, and 4B in resistant Australian cultivars. Our objective was to identify QTL and tightly linked SSR markers for FCR resistance in the partially resistant Australian spring wheat cultivar Sunco using PNW isolates of F. pseudograminerarum in greenhouse and field based screening nurseries. A second objective was to compare heritabilities of FCR resistance in multiple types of disease assaying environments (seedling, terrace, and field) using multiple disease rating methods. Two recombinant inbred line (RIL) mapping populations were derived from crosses between Sunco and PNW spring wheat cultivars Macon and Otis. The Sunco/Macon population comprised 219 F(6):F(7) lines and the Sunco/Otis population comprised 151 F(5):F(6) lines. Plants were inoculated with a single PNW F. pseudograminearum isolate (006-13) in growth room (seedling), outdoor terrace (adult) and field (adult) assays conducted from 2008 through 2010. Crown and lower stem tissues of seedling and adult plants were rated for disease severity on several different scales, but mainly on a numeric scale from 0 to 10 where 0 = no discoloration and 10 = severe disease. Significant QTL were identified on chromosomes 2B, 3B, 4B, 4D, and 7A with LOD scores ranging from 3 to 22. The most significant and consistent QTL across screening environments was located on chromosome 3BL, inherited from the PNW cultivars Macon and Otis, with maximum LOD scores of 22 and 9 explaining 36 and 23% of the variation, respectively for the Sunco/Macon and Sunco/Otis populations. The SSR markers Xgwm247 and Xgwm299 flank these QTL and are being validated for use in marker-assisted selection for FCR resistance. This is the first report of QTL associated with FCR resistance in the US.

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Fusarium crown rot resistance QTL on chromosome 3BL identified across two Sunco/Macon population growth room seedling testing environments utilizing a 0–10 rating system adapted from Nicol et al. (2007) (a), a crown rot severity index (Mitter et al. 2006) (b), and a leaf sheath summation of symptomatic leaves (Wildermuth and McNamara 1994) (c)
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Fig2: Fusarium crown rot resistance QTL on chromosome 3BL identified across two Sunco/Macon population growth room seedling testing environments utilizing a 0–10 rating system adapted from Nicol et al. (2007) (a), a crown rot severity index (Mitter et al. 2006) (b), and a leaf sheath summation of symptomatic leaves (Wildermuth and McNamara 1994) (c)

Mentions: A major QTL, Qcrs.wsu-3BL, inherited from Macon, were identified on chromosome 3BL and was detected in all three growth room seedling assays and to lesser extents in field assays (Tables 1, 4; Fig. 1). The Qcrs.wsu-3BL QTL are flanked by two microsatellite (SSR) markers, Xgwm299 and Xgwm247, covering a region of 1.8 cM (Fig. 1). The SSR marker Xgwm299 is located approximately 1.2 cM away from the peak LOD value in the QTL region. All three rating assessment systems successfully identified this major QTL for the Sunco/Macon population in the 3BL region (Fig. 2). Other significant QTL were identified on chromosomes 1D and 4D. The markers wPt-3342 and wPt-731500, located on chromosome 3BL, were single markers that had significant main effects across all three testing environments (growth room, terrace, and field) (see Online resource 4). The main effects for the SSR markers Xgwm247, Xgwm181, and Xgwm299 were significant only in the growth room screens. Xgwm299 was associated with FCR severity in the field screen at p = 0.06 (see Online Resource 4) and was the only marker with suggestive QTL identified from the field in the 3BL QTL location (Table 4).Fig. 2


Identification of quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in multiple assay environments in the Pacific Northwestern US.

Poole GJ, Smiley RW, Paulitz TC, Walker CA, Carter AH, See DR, Garland-Campbell K - Theor. Appl. Genet. (2012)

Fusarium crown rot resistance QTL on chromosome 3BL identified across two Sunco/Macon population growth room seedling testing environments utilizing a 0–10 rating system adapted from Nicol et al. (2007) (a), a crown rot severity index (Mitter et al. 2006) (b), and a leaf sheath summation of symptomatic leaves (Wildermuth and McNamara 1994) (c)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3351592&req=5

Fig2: Fusarium crown rot resistance QTL on chromosome 3BL identified across two Sunco/Macon population growth room seedling testing environments utilizing a 0–10 rating system adapted from Nicol et al. (2007) (a), a crown rot severity index (Mitter et al. 2006) (b), and a leaf sheath summation of symptomatic leaves (Wildermuth and McNamara 1994) (c)
Mentions: A major QTL, Qcrs.wsu-3BL, inherited from Macon, were identified on chromosome 3BL and was detected in all three growth room seedling assays and to lesser extents in field assays (Tables 1, 4; Fig. 1). The Qcrs.wsu-3BL QTL are flanked by two microsatellite (SSR) markers, Xgwm299 and Xgwm247, covering a region of 1.8 cM (Fig. 1). The SSR marker Xgwm299 is located approximately 1.2 cM away from the peak LOD value in the QTL region. All three rating assessment systems successfully identified this major QTL for the Sunco/Macon population in the 3BL region (Fig. 2). Other significant QTL were identified on chromosomes 1D and 4D. The markers wPt-3342 and wPt-731500, located on chromosome 3BL, were single markers that had significant main effects across all three testing environments (growth room, terrace, and field) (see Online resource 4). The main effects for the SSR markers Xgwm247, Xgwm181, and Xgwm299 were significant only in the growth room screens. Xgwm299 was associated with FCR severity in the field screen at p = 0.06 (see Online Resource 4) and was the only marker with suggestive QTL identified from the field in the 3BL QTL location (Table 4).Fig. 2

Bottom Line: The most significant and consistent QTL across screening environments was located on chromosome 3BL, inherited from the PNW cultivars Macon and Otis, with maximum LOD scores of 22 and 9 explaining 36 and 23% of the variation, respectively for the Sunco/Macon and Sunco/Otis populations.The SSR markers Xgwm247 and Xgwm299 flank these QTL and are being validated for use in marker-assisted selection for FCR resistance.This is the first report of QTL associated with FCR resistance in the US.

View Article: PubMed Central - PubMed

Affiliation: Department of Crop and Soil Sciences, Washington State University, P.O. Box 6420, Pullman, WA 99164-6420, USA. Grant.Poole@sa.gov.au

ABSTRACT
Fusarium crown rot (FCR), caused by Fusarium pseudograminearum and F. culmorum, reduces wheat (Triticum aestivum L.) yields in the Pacific Northwest (PNW) of the US by as much as 35%. Resistance to FCR has not yet been discovered in currently grown PNW wheat cultivars. Several significant quantitative trait loci (QTL) for FCR resistance have been documented on chromosomes 1A, 1D, 2B, 3B, and 4B in resistant Australian cultivars. Our objective was to identify QTL and tightly linked SSR markers for FCR resistance in the partially resistant Australian spring wheat cultivar Sunco using PNW isolates of F. pseudograminerarum in greenhouse and field based screening nurseries. A second objective was to compare heritabilities of FCR resistance in multiple types of disease assaying environments (seedling, terrace, and field) using multiple disease rating methods. Two recombinant inbred line (RIL) mapping populations were derived from crosses between Sunco and PNW spring wheat cultivars Macon and Otis. The Sunco/Macon population comprised 219 F(6):F(7) lines and the Sunco/Otis population comprised 151 F(5):F(6) lines. Plants were inoculated with a single PNW F. pseudograminearum isolate (006-13) in growth room (seedling), outdoor terrace (adult) and field (adult) assays conducted from 2008 through 2010. Crown and lower stem tissues of seedling and adult plants were rated for disease severity on several different scales, but mainly on a numeric scale from 0 to 10 where 0 = no discoloration and 10 = severe disease. Significant QTL were identified on chromosomes 2B, 3B, 4B, 4D, and 7A with LOD scores ranging from 3 to 22. The most significant and consistent QTL across screening environments was located on chromosome 3BL, inherited from the PNW cultivars Macon and Otis, with maximum LOD scores of 22 and 9 explaining 36 and 23% of the variation, respectively for the Sunco/Macon and Sunco/Otis populations. The SSR markers Xgwm247 and Xgwm299 flank these QTL and are being validated for use in marker-assisted selection for FCR resistance. This is the first report of QTL associated with FCR resistance in the US.

Show MeSH