Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1919. / Cover title. Reprinted from Journal of agricultural research, vol. XVI, no. 11 (17 Mar. 1919). Includes bibliographical references (p. 301-303).

The fungus Fusarium sacchari (Butler) Gams causes stem rot in sugarcane especially in association with the stem borer Eldana saccharina Walker. Sugarcane plants tolerant to F. sacchari PNG40 were obtained by chemical mutagenesis and in vitro selection during somatic embryogenesis and plantlet regeneration on media containing F. sacchari culture filtrates (CF), followed by selection in the greenhouse. Somaclonal variants tolerant to F. sacchari PNG40 CF were established by treatment of calli with ethyl methanesulphonate (EMS) and various selection treatments. Investigations were conducted to test the effect of varying CF concentrations and the culture developmental stages (embryo maturation, embryo germination and plantlets) that were most effective in screening calli and plants. Incorporation of CF (0-100 ppm) in the media, at either embryo maturation or germination stages, resulted in significant callus necrosis, and consequent decreased plantlet yield. The highest callus necrosis of 95.55 ± 0.9 % and the lowest plant yield of 1.4 ± 0.45 plants/0.2 g were obtained after inclusion of 100 ppm CF in the germination medium compared with 61.5 ± 3.8 % and 43.8 ± 5.6 plants/0.2 g in the maturation medium, respectively. Exposure of whole plants with trimmed roots to 0-1500 ppm CF resulted in inhibition of root re-growth, with the 1500 ppm CF treatment having the greatest negative effect. Subsequent treatments involved immersing in vitro plantlets in varying concentrations of F. sacchari conidial suspensions. This resulted in 33.3 % and 100 % mortality with 103 and 105 conidia/ml treatments, respectively. Control and EMS-treated calli and potentially tolerant regenerated plants were selected using the established CF and inoculation treatments. Plants from EMS treatments displayed more varying root length. More plants with increased root growth, in the presence of CF, were produced from these treatments than from non-EMS treatments, indicating the ability of EMS to induce somaclonal variation. These putative tolerant plants were inoculated with PNG40 and those selected using CF in vitro were symptomless whilst the positive controls (plants unexposed to CF) were symptomatic. Re-isolation of Fusarium from the inoculated plants and identifying isolates as PNG40 using ISSR analysis confirmed tolerance of the asymptomatic plants and the fungus as the causal agent of the observed symptoms. This confirmed that tolerance to CF correlates to tolerance to F. sacchari PNG40. Future work includes testing stability of tolerance in the field and after sexual reproduction, and use of this protocol to produce plants that permit endophytic PNG40 colonisation towards biological control of E. saccharina. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2012.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 126-132).

Thesis (M. Sc.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Oct. 20, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Plant Science, Department of Agricultural, Food and Nutritional Science, University of Alberta." Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2004. / Includes bibliographical references.

Thesis (M.Sc.)(Biochemistry)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 55-59). Also available on the World Wide Web.

Fusarium subglutinans sensu lato is a complex of fungi, which are the causal agents of important diseases on a wide variety of plants. Two important diseases caused by F. subglutinans sensu lato are pitch canker and mango malformation. F. subglutinans sensu lato isolates causing pitch canker on pine trees have been described as a separate species, F. circinatum. whereas F. subglutinans sensu lato isolates associated with mango malformation have not been formally described. The objective of study was to clarify the taxonomy and population genetics of the pitch canker and mango malformation fungi residing in the Gibberellafujikuroi complex. The introductory chapter of this thesis provides a review of the taxonomic classifications used for Fusarium spp. in the G. fujikuroi complex. In addition, the current knowledge pertaining to the population structure of the pitch canker and mango malformation fungi is discussed. In the second chapter the occurrence of F. circinatum was investigated in Mexico. Fusarium isolates were collected from pine trees in Mexico and identified as F. circinatum. Morphology, sexual compatibility studies, pathogenicity tests and histone H3-RFLPs were used to identify and characterize this fungus. The pitch canker fungus, F. circinatum and its teleomorph, G. circinata has been recently described. However, the name G. circinata is invalid, because insufficient information was provided to characterize the type specimen in the description. Additional information and a selection of F. circinatum isolates were, therefore, obtained and studies were undertaken in order to validate the description of G. circinata. The teleomorph G. circinata was validated and morphological criteria were shown to clearly distinguish F. circinatum from other F. subglutinans sensu lato isolates. Chapter four presents a study aimed at better understanding relationships between populations of F. circinatum from different geographical areas. For this study co¬dominant molecular markers were developed. These were then used to determine the genetic diversity, genetic distance and migration between different F. circinatum populations. Analysis revealed a high diversity in the Florida population and a low diversity in the South African population. Genetic analysis also indicated that the South African F. circinatum population originated in Mexico. In chapter five, the influence of sexual reproduction on the F. circinatum populations sampled over ten years in South Africa were studied. Sexual compatibility, vegetative compatibility and allelic diversity that were determined using polymorphic markers, developed in chapter four, were used. These results suggested that sexual reproduction is occurring more frequently in the more recently collected populations than in the initial population. Mango malformation is an important disease in mango growing areas. The study presented in chapter six indicated that this disease is associated with two distinct Fusarium spp. in the section Liseola. The two new Fusarium spp. are thus described as F. mangiferae and F. sterilihyphosum using morphological criteria In chapter seven, the distribution and vegetative compatibility of both F. mangiferae and F. sterilihyphosum was determined for the South Africa populations. Results revealed that each of these species differ in their distribution in South Africa. Vegetative compatibility tests also suggest that both species represent single genets in South Africa. Fusarium subglutinans sensu lato isolates associated with pme and mango are economically important fungi. The focus of the studies presented in this thesis has been on the taxonomy and population genetics of these fungi, with special reference to their occurrence in South Africa. Each of the chapters will contributes towards a better understanding of the taxonomy, population genetics and biology of these fungi. / Thesis (PhD)--University of Pretoria, 2006. / Microbiology and Plant Pathology / Unrestricted

A necrosis at the tip of cones was observed on hop (Humulus lupulus), cultivar "Nugget", grown in Oregon in the early 1990's. Fusarium sambucinum and F. avenaceum were recovered from symptomatic cones in 1998 and preliminary inoculation experiments suggested both Fusarium species could cause hop cone necrosis. Studies were carried out to (1) examine pathogenicity and demonstrate Koch's postulates for hop cone tip blight using isolates of F. avenaceum and F. sambucinum obtained from hop cones; (2) examine isolates of F. avenaceum and F. sambucinum derived from other diseased plant hosts, and other Fusarium species derived from hop cones, for ability to cause cone necrosis; and (3) survey commercial fields to determine Fusarium populations on 'Nugget' cone parts. Isolates ofF. avenaceum and F. sambucinum recovered from diseased hop cones were used for pathogenicity experiments. In addition, cone inoculations were done with single isolates of F. avenaceum and F. sambucinum from diseased sweet corn roots, one isolate of F. sambucinum recovered from a diseased potato tuber, individual isolates of F. equiseti and F. oxysporum from hop cones. Cones of two hop cultivars, 'Nugget' and 'Willamette', were collected from three different farms on three sampling dates and inoculated with spore suspensions of hop-derived F. avenaceum and F. sambucinum at concentrations of 10��, 1O���, and 10��� conidia/ml to examine dosage effects. Necrosis was evaluated 2, 4, 6, and 8 days after inoculation. Percent cone necrosis decreased as inoculum concentration of either F. avenaceum or F. sambucinum decreased, and was lowest on water-treated cones, for all three sampling dates. The respective Fusarium species were recovered from symptomatic cones. Cone necrosis developed following cone inoculation with F. avenaceum or F. sambucinum from potato or corn. Hop cones inoculated with F. equiseti or F. oxysporum also developed necrosis, but at relatively lower levels compared to the other Fusarium species used for inoculations. For the surveys in commercial hop fields, burr and cone material were collected on five different dates. Fusarium sambucinum was recovered most frequently, but F. avenaceum was also found. Both Fusarium species were recovered from asymptomatic burr and cone materials throughout the growing season. In general, Fusarium species, F. equiseti, F. oxysporum, F. culmorum, F. solani, plus F. avenaceum and F. sambucinum were found more frequently early in the season on stigmatic tissue, and Fusarium recovery decreased as the season progressed. Fusarium prolferatum and F. monilforme were recovered rarely. / Graduation date: 2004

An evaluation of nineteen barley lines using three artificial inoculation methods concluded that spray inoculation was the most reproducible method and provided the greatest discrimination of resistance. Six of the nineteen barley lines were used for proteomic studies to identify defense responses following F. graminearum infection. All lines responded by inducing an oxidative burst and pathogenesis-related proteins. Differences in response magnitude and the proteins activated could be attributed to varying levels of FHB resistance amongst the barley lines. RNA microarray profiling and iTRAQ technology were used to study the interaction between two barley lines under five different treatments testing the effect of the fungus, trichothecene, and their interaction. Resistance was differentiated by the early induction of defense-related genes and the activation of the JA and ethylene defense pathways in Chevron, compared to the induction of a less efficient defense pathway in Stander; observed intra- and inter-cultivar differential responses are discussed. / xvii, 196 leaves : ill. ; 29 cm.