Molecular tools, coupled with unique germplasm stocks and rigorous phenotyping, are
useful for developing a better understanding of qualitative and quantitative disease resistance
genes in plants. The identification of molecular markers linked to all types of resistance
genes provides opportunities for implementing a range of resistance breeding strategies,
ranging from gene pyramiding to gene deployment. This thesis consists of two chapters. The
first describes a disease resistance gene mapping effort and the second describes a disease
resistance gene introgression effort. The number, location, and effects of genes determining
resistance to stripe rust, leaf rust and Barley Yellow Dwarf Virus were determined using a
population of doubled haploid (DH) lines from the cross of Shyri x Galena. Resistance to leaf
rust was qualitatively inherited, and the locus was mapped to the long arm of chromosome 1.
Resistance to stripe rust and BYDV was quantitatively inherited. Multiple QTLs were
detected for each type of resistance. The principal stripe rust resistance QTL was on the
short arm of chromosome 5 and the principal BYDV resistance QTL was on the long arm of
chromosome 1, linked in repulsion phase with the leaf rust resistance gene. Additional QTLs
and QTL x QTL interactions were detected. The majority of the qualitative and quantitative
resistance loci detected in the Shyri x Galena population coincided with Resistance Gene
Analog Polymorphisms (RGAPs) mapped in the same population. These RGAPs were based
on degenerate primers derived from cloned resistance gene sequence motifs. These
associations should be useful for efficient resistance gene mapping and provide an approach
for ultimately isolating and describing quantitative and qualitative resistance genes. The
second chapter describes a molecular marker assisted selection (MMAS) effort to introgress
stripe rust resistance QTLs on chromosomes 4 and 7 into susceptible germplasm. DH lines
were derived form a MMAS backcross-one (BC-1) population, extensively phenotyped for
stripe rust resistance, and genotyped for the introgressed QTLs and background genome.
The resistance QTLs that were introgressed were significant determinants of resistance in the
new genetic background. Additional resistance QTLs were also detected. Together, these
chapters describe an integrated approach to disease resistance gene characterization and
utilization. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33275 |
| Date | 09 December 1998 |
| Creators | Toojinda, Theeryut |
| Contributors | Hayes, Patrick M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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