Genetic Characterization of Wheat Germplasm with Resistance to Fusarium Head Blight (FHB) and Powdery Mildew
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Date
2007-12-20
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Abstract
A dominant powdery mildew resistance gene transferred to the hexaploid germplasm line NC99BGTAG11 from T. timopheevii subsp. armeniacum was mapped distally on the long arm of chromosome 7A. Differential reactions were observed between the resistance gene in NC99BGTAG11, the resistance gene in NC96BGTA4, and the alleles of the Pm1 locus that are also located on chromosome arm 7AL. Observed segregation in F2:3 lines from the cross NC99BGTAG11 x Axminster (Pm1a) and from the cross NC99BGTAG11 x NC96BGTA4 demonstrate that germplasm line NC99BGTAG11 carries a novel powdery mildew resistance gene, which is now designated as Pm37. Analyses of the population with molecular markers indicate that Pm37 is located 16 cM proximal to the Pm1 complex. However, further identification of linked markers is necessary to resolve the location of the resistance gene in NC96BGTA4. Simple sequence repeat (SSR) markers Xgwm332 and Xwmc790 were located 0.5 cM proximal and distal, respectively, to Pm37. Two new EST-derived STS markers were located distal to Pm37 and one marker was closely linked to the Pm1a region.
Quantitative trait loci (QTL) for resistance to Fusarium head blight (FHB) have been mapped in the Chinese cv. Sumai 3 and its derivatives (on 3BS, 5AS, and 6BS), in Wuhan 1 (on 2D and 4B), and in the soft winter (SW) wheat cv. Ernie (on 4BL, 5A, and 3BSc). In this study, we selected 48 molecular markers near or at FHB resistance QTL mapped in Sumai 3, Wuhan 1 and Ernie to haplotype 245 soft winter wheat lines and to evaluate the use of these markers for marker-assisted selection (MAS). Based on the marker data, entries were grouped into 6 main clusters that generally represented breeding programs and/or geographic origin. The Chinese cultivars having the Fhb1 resistance gene were grouped separately from all other entries. The Xsts3B-256 and Xgwm533 markers can be clearly used to identify lines with the Fhb1 resistance gene. The haplotypes at these loci, along with the 3BSc region, suggest that SW wheat cultivars such as Patton, Freedom, and Roane that have been considered important sources of native FHB resistance, may share resistance QTL with Ernie.
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disease resistance, haplotype, powdery mildew, Fusarium head blight, SSR, STS, BLAST
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PhD
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Crop Science
