Stripe rust (Puccinia striiformis f. sp. hordei) is a serious disease of barley that can
cause up to 70% yield loss in susceptible varieties. The fungus is moving northward,
threatening major barley production areas in the US, where most cultivars are susceptible.
Fungicides are available for control of stripe rust, but economic and environmental
considerations favor genetic resistance. Two stripe rust resistance quantitative trait loci
(QTLs) located in chromosomes 4 and 7 have previously been reported. One hundred and
ten doubled haploid progeny from a stripe rust susceptible x resistant cross were derived
using the Hordeum bulbosum technique and phenotyped for agronomic and malting
quality traits in order to assess the importance of linkage drag associated with the mapped
stripe rust resistance QTLs. Data on 33 markers were combined with phenotypic data for
QTL analysis. A molecular marker-assisted backcross program was implemented to
initiate the transfer of the stripe rust resistance loci into susceptible US germplasm. No
negative QTLs for agronomic or malting quality traits were detected within or adjacent to
the intervals that were targeted for marker-assisted selection. A minor leaf rust resistance
QTL, however, was found adjacent to the stripe rust locus on chromosome 7. Linkage
drag in this region could operate in favor of the breeder. Epistatic interaction between the
two stripe rust resistance QTLs confirms the necessity of introgressing both chromosome
intervals. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36114 |
| Date | 20 December 1993 |
| Creators | Prehn, Doris A. |
| Contributors | Hayes, Patrick M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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