Abstract
Yellow spot (Pyrenophora tritici-repentis) is a major foliar disease in wheat
(Triticum aestivum) and it has become more serious in recent years, possibly
due to changes in climate or cultural practice. A major QTL located on the short
arm of wheat chromosome 2B, which explains 30–40% of the phenotypic
variance, has been identified recently. However, the closest marker linked to this
QTL was a DArT marker that is not easy to use in large-scale selection; the
closest PCR-based marker available (2.7 cM) was too far away to be reliably
used for tagging the locus in wheat breeding. For these reasons, studies were
undertaken to develop more closely–linked and user-friendly markers for this
major QTL. Forty-one new markers either synthesised from DArT markers or
identified from the GrainGene database were assessed. From these, a new
PCR-based marker (Rfsts1), located 0.3 cM away from the major QTL, was
developed for marker assisted selection in yellow spot breeding. This marker
linked to the 2BS locus was used to combine with another QTL conferring yellow
spot resistance on chromosome 5BL and the effects of gene pyramiding in
increasing resistance to this disease were investigated. The results indicated
that the combined selection could significantly increase selection efficiency and
accuracy and resulted in genotypes with significantly higher resistance to yellow
spot.
(Triticum aestivum) and it has become more serious in recent years, possibly
due to changes in climate or cultural practice. A major QTL located on the short
arm of wheat chromosome 2B, which explains 30–40% of the phenotypic
variance, has been identified recently. However, the closest marker linked to this
QTL was a DArT marker that is not easy to use in large-scale selection; the
closest PCR-based marker available (2.7 cM) was too far away to be reliably
used for tagging the locus in wheat breeding. For these reasons, studies were
undertaken to develop more closely–linked and user-friendly markers for this
major QTL. Forty-one new markers either synthesised from DArT markers or
identified from the GrainGene database were assessed. From these, a new
PCR-based marker (Rfsts1), located 0.3 cM away from the major QTL, was
developed for marker assisted selection in yellow spot breeding. This marker
linked to the 2BS locus was used to combine with another QTL conferring yellow
spot resistance on chromosome 5BL and the effects of gene pyramiding in
increasing resistance to this disease were investigated. The results indicated
that the combined selection could significantly increase selection efficiency and
accuracy and resulted in genotypes with significantly higher resistance to yellow
spot.
| Original language | English |
|---|---|
| Qualification | Masters |
| Supervisors/Advisors |
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| Publication status | Unpublished - Apr 2015 |