Limits...
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.

Show MeSH
Fusarium crown rot resistance QTL on chromosome 3BS identified in the Sunco/Otis population for the growth room (a), terrace (b), and field (c) environment means rated 0–10 utilizing composite interval mapping
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3351592&req=5

Fig4: Fusarium crown rot resistance QTL on chromosome 3BS identified in the Sunco/Otis population for the growth room (a), terrace (b), and field (c) environment means rated 0–10 utilizing composite interval mapping

Mentions: Single marker and CIM analysis revealed significant QTL on chromosomes 2B, 3B, 4B, and 7A with one major QTL on chromosome 3BL inherited from Otis in the Sunco/Otis population (Table 3; see Online Resource 5; Figs. 3, 4). We again ran mixed model analysis to determine whether marker by environment interaction was significant for those QTL. As with the Sunco/Macon population, the marker by assay interaction term was non-significant for most of the terrace and field assays, supporting our identification of significant marker main effects (see Online Resource 5). There was an exception across the terrace assays for two markers on chromosome 7A for markers wPt-5261 and wPt-0021 both in the 3BL QTL region. The terrace marker by assay interactions on 7A were explained by significantly greater levels of disease in individuals with the Otis allele compared to those with the Sunco allele in 2009. Similar to the Sunco/Macon population, the interactions in the growth room were due to non-crossover interactions.Fig. 3


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 3BS identified in the Sunco/Otis population for the growth room (a), terrace (b), and field (c) environment means rated 0–10 utilizing composite interval mapping
© Copyright Policy
Related In: Results  -  Collection

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

Fig4: Fusarium crown rot resistance QTL on chromosome 3BS identified in the Sunco/Otis population for the growth room (a), terrace (b), and field (c) environment means rated 0–10 utilizing composite interval mapping
Mentions: Single marker and CIM analysis revealed significant QTL on chromosomes 2B, 3B, 4B, and 7A with one major QTL on chromosome 3BL inherited from Otis in the Sunco/Otis population (Table 3; see Online Resource 5; Figs. 3, 4). We again ran mixed model analysis to determine whether marker by environment interaction was significant for those QTL. As with the Sunco/Macon population, the marker by assay interaction term was non-significant for most of the terrace and field assays, supporting our identification of significant marker main effects (see Online Resource 5). There was an exception across the terrace assays for two markers on chromosome 7A for markers wPt-5261 and wPt-0021 both in the 3BL QTL region. The terrace marker by assay interactions on 7A were explained by significantly greater levels of disease in individuals with the Otis allele compared to those with the Sunco allele in 2009. Similar to the Sunco/Macon population, the interactions in the growth room were due to non-crossover interactions.Fig. 3

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