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Comparative analyses identify the contributions of exotic donors to disease resistance in a barley experimental population.

Fang Z, Eule-Nashoba A, Powers C, Kono TY, Takuno S, Morrell PL, Smith KP - G3 (Bethesda) (2013)

Bottom Line: All three genomic regions have been previously identified by quantitative trait locus (QTL) and association mapping.Based on the degree of identity-by-state relative to donor parents, putative donors of resistance alleles were also identified.The successful application of comparative population genetic approaches in this barley breeding experiment suggests that the approach could be applied to other breeding populations that have undergone defined breeding and selection histories, with the potential to provide valuable information for genetic improvement.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.

ABSTRACT
Introgression of novel genetic variation into breeding populations is frequently required to facilitate response to new abiotic or biotic pressure. This is particularly true for the introduction of host pathogen resistance in plant breeding. However, the number and genomic location of loci contributed by donor parents are often unknown, complicating efforts to recover desired agronomic phenotypes. We examined allele frequency differentiation in an experimental barley breeding population subject to introgression and subsequent selection for Fusarium head blight resistance. Allele frequency differentiation between the experimental population and the base population identified three primary genomic regions putatively subject to selection for resistance. All three genomic regions have been previously identified by quantitative trait locus (QTL) and association mapping. Based on the degree of identity-by-state relative to donor parents, putative donors of resistance alleles were also identified. The successful application of comparative population genetic approaches in this barley breeding experiment suggests that the approach could be applied to other breeding populations that have undergone defined breeding and selection histories, with the potential to provide valuable information for genetic improvement.

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Related in: MedlinePlus

Breeding history of the Closed and Reopened populations. Filled shapes designate individuals carrying Fusarium head blight (FHB) resistance and/or reduced deoxynivalenol (DON) accumulation. The Reopened population acquired reduced FHB severity and DON concentration through the introgression from 13 donor lines between 1992 and 2004.
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fig1: Breeding history of the Closed and Reopened populations. Filled shapes designate individuals carrying Fusarium head blight (FHB) resistance and/or reduced deoxynivalenol (DON) accumulation. The Reopened population acquired reduced FHB severity and DON concentration through the introgression from 13 donor lines between 1992 and 2004.

Mentions: Breeding lines for this study were derived from the six-row malting barley breeding program at the University of Minnesota, which began in the early 1900s. The genetic base of this breeding population is quite narrow, with ∼50% of the six-row germplasm in North America tracing to five ancestors (Martin et al. 1991). In the early 1990s, the original advanced cycle breeding strategy was maintained for part of the breeding program while a new strategy that introduced exotic sources of FHB resistance was implemented in parallel. This resulted in two parallel breeding populations within the breeding program with different breeding histories. To compare these two populations, we created two panels of 120 breeding lines that were representative of the two populations. The Closed panel comprises lines from the advanced cycle breeding program (elite × elite) with a relatively closed pedigree, i.e., few new founders were introduced after 1958 when the strategy was initiated (Condón et al. 2008; Condón et al. 2009). The Reopened panel comprises lines from families derived from the introduction of 13 new donors to the Closed population in response to the FHB epidemic (Figure 1). The lines in each panel were selected from a period of transition between advanced cycle breeding and introduction of disease-resistant parents (2003–2007), such that we could adequately sample both breeding populations. Lines in each panel were selected to maximize the number of families represented within each population; the Closed panel sampled 32 (94%) of 34 families in the Closed population that advanced to preliminary yield trials, and the Reopened panel sampled 52 (87%) of 60 families in the Reopened population. Lines selected for both panels were based on seed or DNA availability, with preference given to lines with malting quality data.


Comparative analyses identify the contributions of exotic donors to disease resistance in a barley experimental population.

Fang Z, Eule-Nashoba A, Powers C, Kono TY, Takuno S, Morrell PL, Smith KP - G3 (Bethesda) (2013)

Breeding history of the Closed and Reopened populations. Filled shapes designate individuals carrying Fusarium head blight (FHB) resistance and/or reduced deoxynivalenol (DON) accumulation. The Reopened population acquired reduced FHB severity and DON concentration through the introgression from 13 donor lines between 1992 and 2004.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815057&req=5

fig1: Breeding history of the Closed and Reopened populations. Filled shapes designate individuals carrying Fusarium head blight (FHB) resistance and/or reduced deoxynivalenol (DON) accumulation. The Reopened population acquired reduced FHB severity and DON concentration through the introgression from 13 donor lines between 1992 and 2004.
Mentions: Breeding lines for this study were derived from the six-row malting barley breeding program at the University of Minnesota, which began in the early 1900s. The genetic base of this breeding population is quite narrow, with ∼50% of the six-row germplasm in North America tracing to five ancestors (Martin et al. 1991). In the early 1990s, the original advanced cycle breeding strategy was maintained for part of the breeding program while a new strategy that introduced exotic sources of FHB resistance was implemented in parallel. This resulted in two parallel breeding populations within the breeding program with different breeding histories. To compare these two populations, we created two panels of 120 breeding lines that were representative of the two populations. The Closed panel comprises lines from the advanced cycle breeding program (elite × elite) with a relatively closed pedigree, i.e., few new founders were introduced after 1958 when the strategy was initiated (Condón et al. 2008; Condón et al. 2009). The Reopened panel comprises lines from families derived from the introduction of 13 new donors to the Closed population in response to the FHB epidemic (Figure 1). The lines in each panel were selected from a period of transition between advanced cycle breeding and introduction of disease-resistant parents (2003–2007), such that we could adequately sample both breeding populations. Lines in each panel were selected to maximize the number of families represented within each population; the Closed panel sampled 32 (94%) of 34 families in the Closed population that advanced to preliminary yield trials, and the Reopened panel sampled 52 (87%) of 60 families in the Reopened population. Lines selected for both panels were based on seed or DNA availability, with preference given to lines with malting quality data.

Bottom Line: All three genomic regions have been previously identified by quantitative trait locus (QTL) and association mapping.Based on the degree of identity-by-state relative to donor parents, putative donors of resistance alleles were also identified.The successful application of comparative population genetic approaches in this barley breeding experiment suggests that the approach could be applied to other breeding populations that have undergone defined breeding and selection histories, with the potential to provide valuable information for genetic improvement.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.

ABSTRACT
Introgression of novel genetic variation into breeding populations is frequently required to facilitate response to new abiotic or biotic pressure. This is particularly true for the introduction of host pathogen resistance in plant breeding. However, the number and genomic location of loci contributed by donor parents are often unknown, complicating efforts to recover desired agronomic phenotypes. We examined allele frequency differentiation in an experimental barley breeding population subject to introgression and subsequent selection for Fusarium head blight resistance. Allele frequency differentiation between the experimental population and the base population identified three primary genomic regions putatively subject to selection for resistance. All three genomic regions have been previously identified by quantitative trait locus (QTL) and association mapping. Based on the degree of identity-by-state relative to donor parents, putative donors of resistance alleles were also identified. The successful application of comparative population genetic approaches in this barley breeding experiment suggests that the approach could be applied to other breeding populations that have undergone defined breeding and selection histories, with the potential to provide valuable information for genetic improvement.

Show MeSH
Related in: MedlinePlus