"November, 2003" / Bibliography: leaves 174-191. / viii, 196 leaves : ill. (some col.), photos (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This study aims to identify and characterise novel alleles for key malting quality genes from wild barley, wild barley being a source of novel genetic variation that could be exploited to develop superior barley varieties. / Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2004

Bibliography: leaves 132-155. / viii, 155 leaves : ill., plates, charts (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / A putative callose synthase gene, designated HvGSL1 cDNA is siolated from barley and its involvement in callose biosynthesis is investigated. A near-full length HvGSL1 cDNA encoded a protein showing approximately 30% identitly with that of yeast FKS genes at the amino acid level. The function of this geen was investigated by heterologous expression, protein purification, immunochemistry and mass spectrometric analysis. Results provide strong evidence that the gene encodes a protein which is associated with callose synthase activity, and is likely to encode the catalytic subunit of the synthase complex. / Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2003

Bibliography: leaves 183-211. This study evaluates the backcross breeding method for the introgression in barley of agronomically important traits into a malting quality background using molecular markers.

No description available.

Plants that are heterozygous for genetic markers but do not produce segregating progeny may be suspected of carrying a mutation conditioning apomixis. Seed stocks in which heterozygous plants could be identified phenotypically were treated with a chemical mutagen. These seed stocks were heterozygous for recessive genetic markers, and/or heterozygous for a chromosome translocation. Spikes from heterozygous M1 plants were harvested and seeded in bulk. Spikes from heterozygous M2 plants were harvested and planted in M3 rows. The M3 rows were observed for the absence of segregating progeny and/or were observed cytologically for the presence of a heterozygous translocation. M3 rows not segregating for the genetic markers were crossed onto plants homozygous for the genetic markers. The F1 progenies were observed for an expected ratio of 1 normal: 1 recessive plant. All nonsegregating lines were found to be non-heterozygous. These lines most likely occurred due to seed and pollen contamination or were the result of crossing over between genetic markers. Fertile M2 plants were harvested from the treated heterozygous translocation seed stock. Normally, barley plants heterozygous for a translocation will produce semisterile spikes. Plants that would normally be semisterile but are fertile could be carrying a mutation conditioning apomixis. Progeny of the fertile M2 plants were examined cytologically for the presence of the heterozygous translocation. All selected lines contained the normal seven pairs of chromosomes and were the result of seed or pollen contamination. Seed stocks which could eliminate the problem of contamination in future experiments were developed and discussed. Haploviable mutants closely linked with the male sterile locus, msg2, were isolated in these seed stocks. Haploviable mutants are recognized by upset genetic ratios of alleles linked with the mutant. Selfed progenies of plants carrying a haploviable mutation contained fertile and male sterile plants in about a 1:1 ratio. Mostly male sterile progenies were obtained when plants heterozygous for the haploviable mutant and the male sterile allele were crossed onto male sterile plants. Four lines containing haploviable mutants were evaluated for their usefulness in producing all male sterile lines for hybrid barley production.

No description available.

Graduation date: 1994

Making quality and winterhardiness in barley are "ultimate" phenotypes composed of component, quantitatively inherited traits. A 69-point genome map of the seven chromosomes of barley was used, in conjunction with multi-environment phenotypes for grain yield and malting quality, to determine the chromosome locations of quantitative trait loci (QTLs). A combined analysis of the two environments identified QTLs that were both common and unique to each environment. Dispersed QTLs with positive relationships provide ready targets for marker-assisted selection. Overlapping QTLs for agronomic and making quality QTLs with favorable alleles contributed by alternate parents will require further, higher resolution mapping to determine if negative relationships are due to linkage or pleiotropy. There is preliminary evidence for orthologous agronomic trait and malting QTLs in barley. This QTL analysis will hopefully assist in the rapid development of winter making varieties that will maximize the profitability of Oregon barley production. / Graduation date: 1994

Graduation date: 1991

Barley row-type describes the number of grains present at a node on the barley spike. Two forms exist amongst cultivated barley: two-rowed with only the central of three spikelets fertile producing a single grain at a node and six-rowed with all three spikelets fertile, producing three grain at a node. Twelve regions of the barley genome have been associated with the row-type character with specific genes identified at three loci, <i>VRS1</i>, <i>VRS4</i> and <i>INT-C</i>. Advancements in the understanding of the genetic control underpinning barley row-type enables the identification of potential mechanisms for improving yield and yield architecture within the cereals.  This study used genetic linkage mapping in segregating F2 populations to refine the genetic location of the row-type locus, <i>VRS3</i>, to 16 candidate genes on barley chromosome 1H. Sequencing candidate loci in 32 <i>vrs3</i> induced mutant alleles identified <i>VRS3</i> to be a highly conserved JmjC histone demethylase, with two natural alleles within European cultivated barley. <i>VRS3</i> was further characterised as a potential means of improving grain uniformity within cultivated six-rowed barley, through phenotypic assessment of grain size in varying allele combinations of <i>VRS3</i>, <i>VRS1</i> and <i>INT-C</i>. The addition of six-rowed alleles at these loci was found to improve balance between central and lateral grain parameters, resulting in a more uniform grain sample. Analysis of gene expression found <i>Vrs3</i> to be constitutively expressed across a diverse panel of barley tissues. Moreover, detailed study within the developing inflorescence suggests a role for <i>Vrs3</i> in the regulation of the row-type genes <i>VRS1</i> and <i>INT-C. </i>