Characterization of Resistance to Fusarium Head Blight in an Eastern U.S. Soft Red Winter Wheat Population

Abstract

Host resistance is important to control Fusarium head blight (FHB) ), caused by the fungus Fusarium graminearum (Schwabe) [teleomorph: Gibberella zeae (schw.) Petch], in wheat (Triticum aestivum L.). Effective breeding requires understanding the genetics of resistance in breeding populations. Our objective was to deduce the genetics of FHB resistance in eastern U.S. soft red winter wheat (SRWW) by estimating heritability, means, and phenotype frequencies. We evaluated the FHB index of 2983 lines from 223 parents in a series of single‐ and multiyear trials conducted in inoculated FHB nurseries. The mean index of all lines (23.8%) was similar to that of the moderate resistant check (19.7%), and the distribution was often skewed toward low index values. Without selection, 41% of all lines had moderate resistance and 70% of all crosses produced such lines. Entry‐mean heritability for index generally exceeded 0.65 and selection for lower index reduced the index by −37%. The moderate resistance arose from many SRWW parents with varying levels of FHB resistance. The genetics of resistance in this population is probably characterized by a relatively high frequency of resistance alleles at multiple loci, dispersed over many parents that differ in allele content at loci controlling FHB resistance. This population should provide excellent gain from recurrent selection and complement current marker‐assisted selection efforts.

Identifying Quantitative Trait Loci for Economic Traits in an Elite Soft Red Winter Wheat Population

“…A susceptible (‘Pioneer 2545’), moderate resistant (‘Freedom’), and resistant (‘Truman’) check was included four times in each replication. Inoculation was achieved by a combination of spraying a spore suspension and the use of grain spawn as described by Sneller et al (2010). Five isolates of F. graminearum , collected from naturally infected wheat kernels were grown on malt extract agar.…”

Population Structure, Linkage Disequilibrium, and Genetic Diversity in Soft Winter Wheat Enriched for Fusarium Head Blight Resistance

“…Electrophoresis was performed on an ABI 3130 (Applied Biosystems). The software GeneMarker v1.85 (SoftGenetics, 2009) was used to analyze and call SSR alleles, which were manually checked for accuracy.…”

Potential and limits to unravel the genetic architecture and predict the variation of Fusarium head blight resistance in European winter wheat (Triticum aestivum L.)

“…Large effect quantitative trait locus (QTL) such as Fhb1 and Fhb5 were identified in crosses with the exotic Sumai 3 and CM82036 donor lines (Becher et al, 2013). However, despite worldwide efforts, the frequency of favorable Fhb1 and Fhb5 alleles is still low in European and US elite wheat germplasm (Sneller et al, 2010;Bernardo et al, 2012;Miedaner and Korzun, 2012). One reason is the long time need to reduce linkage drag associated with marker-based introgression of Fhb1 or Fhb5 (Miedaner and Korzun, 2012).…”

“…One reason is the long time need to reduce linkage drag associated with marker-based introgression of Fhb1 or Fhb5 (Miedaner and Korzun, 2012). In contrast to Fhb1 and Fhb5, the effects of FHB resistance QTL that were identified in adapted European or US wheat germplasm and thus are not associated with linkage drag are only rather small (Buerstmayr et al, 2008;Löffler et al, 2009;Sneller et al, 2010). This so far hinders an efficient application of marker-assisted selection for FHB resistance for QTL alleles identified in adapted elite germplasm.…”