Typewritten copy Comparative study of genes for resistance to bunt (Tilletia caries (D.C.) Tul. and T. foetida (Wallr.) Liro); Cytological investigations in Phalaris called part 2.

Copy of author's previously published article inserted. / Bibliography: leaves 60-75. / viii, 75, [40] leaves, [24] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Crop Protection, 1995?

Includes bibliographical references. / xiv, 210 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1995

Copy of author's previously published article inserted. Bibliography: leaves 60-75.

Includes bibliographical references.

Includes bibliographical references (leaves 265-296). Pathogens associated with root damage were investigated in the Murray Mallee region of South Australia over the 1987-1989 growing seasons. Occurence of fungal species and the root lesion nematode (Pratylenchus neglectus) was assessed, and related to the appearance and severity of symptoms on the roots. Field experiments were supplemented with innoculation tests in the glasshouse and laboratory.

Mycosphaerella graminicola (anamorph Septoria tritici) causes Septoria tritici blotch, a globally important disease of winter wheat. Resistance and pathogenicity generally vary quantitatively. The pathogen reproduces both sexually and asexually, and the pathogen population is highly genetically variable. Several unresolved questions about the epidemiology of this pathosystem are addressed by this research. Among them are whether cultivar-isolate specificity exists, how partial host resistance affects pathogen aggressiveness and sexual reproduction, and how host genotype mixtures influence epidemic progression and pathogenicity. At its release in 1992, the cultivar Gene was highly resistant to M. graminicola, but that resistance had substantially dissolved by 1995. Six of seven isolates collected in 1997 from field plots of Gene were virulent to Gene seedlings in the greenhouse, while 14 of 15 isolates collected from two other cultivars were avirulent to Gene. Gene apparently selected for strains of M. graminicola with specific virulence to it. In a two-year experiment, isolates were collected early and late in the growing season from field plots of three moderately resistant and three susceptible cultivars, and tested on seedlings of the same cultivars in the greenhouse. Isolates were also collected from plots of two susceptible cultivars sprayed with a fungicide to suppress epidemic development. Isolate populations were more aggressive when derived from moderately resistant than from susceptible cultivars, and more aggressive from fungicide-sprayed plots than from unsprayed plots of the same cultivars. Over 5,000 fruiting bodies were collected in three years from replicated field plots of eight cultivars with different levels of resistance. The fruiting bodies were identified as M. graminicola ascocarps or pycnidia, or other. In all three years, the frequency of ascocarps was positively correlated with cultivar susceptibility, as measured by area under the disease progress curve, and was also positively associated with epidemic intensity. For three years, four 1:1 mixtures of a moderately resistant and a susceptible wheat cultivar were planted in replicated field plots. Isolates from the plots were inoculated as bulked populations on greenhouse-grown seedlings of the same four cultivars. Mixture effects on disease progression varied among the years, and were moderately correlated with mixture effects on pathogenicity. / Graduation date: 2002

Bibliography: leaves 318-347. / ix, 347 [24] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / A major problem in the production of agricultural crops including wheat, is the damage caused by destructive plant parasitic nematodes, among these the root lesion nematode (Pratylenchus spp.) The association of P. neglectus with fungi in ceraeal root disease has been reported. Infection is associated with leaf yellowing, which reduces plant photosynthesis and grain yield. In nematode infested soil, well fertilized crops are usually less affected. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1996?

Errata slip inserted. / Bibliogaphy: leaves [93-109]. / x, 92, [17] leaves, [20] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Identifes and maps markers associated with the quality traits of grain protein content, milling yield and flour colour, and with genes resistant to stem- and leaf-rust diseases in wheat. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, Waite Agricultural Research Institute, 1998

Includes bibliographical references (leaves 265-296). / vi, 296 leaves, [14] leaves of plates : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Pathogens associated with root damage were investigated in the Murray Mallee region of South Australia over the 1987-1989 growing seasons. Occurence of fungal species and the root lesion nematode (Pratylenchus neglectus) was assessed, and related to the appearance and severity of symptoms on the roots. Field experiments were supplemented with innoculation tests in the glasshouse and laboratory. / Thesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1991