A genome-wide association study of resistance to the yellow rust pathogen (Puccinia striiformis f. sp. tritici) in elite UK wheat germplasm

Bansept, Pauline (2013) A genome-wide association study of resistance to the yellow rust pathogen (Puccinia striiformis f. sp. tritici) in elite UK wheat germplasm. Doctoral thesis, University of East Anglia.

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Abstract

ABSTRACT
Pauline G. M. Bansept-Basler, 2013
A genome wide association study of resistance to the yellow rust
pathogen (Puccinia striiformis f. sp. tritici) in elite UK wheat germplasm
Identification of marker-trait associations (MTA) in germplasm relevant to
breeding program via association mapping (AM) can be an effective way to identify
loci useful for selection. This approach does not require the generation of specific
mapping populations and takes advantage of historical phenotypic data. In the
present study, an association panel of 327 bread wheat varieties have been assembled
and genotyped with 1806 DArT markers. Genetic structure analysis revealed a low
stratification of the panel based on geographical origin (UK versus mixed European
varieties) and a close relatedness between lines, which is confirmed by pedigree
information. Historical evaluations against the yellow rust pathogen (Puccinia
striiformis f.sp. tritici (Pst)) carried in the United Kingdom between 1990 and 2009,
as well as de novo evaluations against recent Pst races have been collected and
analysed for MTAs.
Association scans considering historical data focused on specific Pst
pathotypes and de novo seedling tests identified markers linked to known racespecific
Yr genes Yr6, Yr7, Yr9, Yr17 and Yr32.
When evaluated against current Pst races in the field, 35% of the lines from
the panel presented repeatedly a high level of resistance (Area Under the Disease
Progress Curve relative<0.2) which is due to the presence of seedling resistances as
well as adult plant resistances within the lines. AM with de novo phenotypes
revealed 23 MTA groups pointing to potential resistance loci, 14 of them were also
identified with historical data and six seemed to point to adult plant resistance loci on
chromosomes 2A, 2B, 3A, 6A, 6B and 7A.
These results confirm the value of AM using historical data for QTL
discovery and suggest the availability of diverse sources of yellow rust resistances
within wheat elite UK germplasm.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Mia Reeves
Date Deposited: 06 Mar 2014 12:46
Last Modified: 06 Mar 2014 12:46
URI: https://ueaeprints.uea.ac.uk/id/eprint/47970
DOI:

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