Browsing Faculty of Graduate Studies (Electronic Theses and Practica) by Subject "15-ADON"
Now showing 1 - 2 of 2
Results Per Page
- ItemOpen AccessFusarium head blight of wheat: evaluation of the efficacies of fungicides towards Fusarium graminearum 3-ADON and 15-ADON isolates in spring wheat and assess the genetic differences between 3-ADON isolates from Canada and China(2011-01-17T20:30:46Z) Amarasinghe, Chami Chathurangi; Brule-Babel, Anita (Plant Science) Gilbert, Jeannie (Cereal Research Centre, Agriculture and Agri-Food Canada) Tamburic-Ilincic, Lily (Plant Science); Fernando, Dilantha (Plant Science)Fusarium head blight (FHB), caused mainly by Fusarium graminearum, is one of the most destructive global diseases of small cereal grains worldwide. The most devastating effect of this disease is the deposition of mycotoxins in the grain. Deoxynivalenol (DON) and its analogs 3-ADON, 15-ADON and NIV are the major mycotoxins produced by the fungus. The chemotype, 15-ADON is more prevalent in North America, but recently a chemotypic shift has been observed. The rapid emergence of the 3-ADON chemotype over the traditional 15-ADON chemotype is a major concern in North America. The studies in this thesis were focused on understanding the behaviour of the 3-ADON and 15-ADON chemotypes and the possible reasons for the rapid chemotypic shift.
- ItemOpen AccessGenetic analysis of resistance to Fusarium head blight in wheat (Triticum spp.) using phenotypic characters and molecular markers(2010-10-26T17:27:54Z) Malihipour, Ali; Brûlé-Babel, Anita (Plant Science) Piercey-Normore, Michele (Biological Sciences) Fedak, George (Biological Sciences) Xue, Steven (USDA-ARS, Fargo, ND); Gilbert, Jeannie (Biological Sciences)Fusarium head blight (FHB), caused mainly by Fusarium graminearum (teleomorph: Gibberella zeae), is one of the most damaging diseases of wheat. A ‘Brio’/‘TC 67’ spring wheat population was used to map quantitative trait loci (QTLs) for resistance to FHB, and to study the association of morphological and developmental characteristics with FHB resistance. Interval mapping (IM) detected a major QTL on chromosome 5AL for resistance to disease severity (type II resistance) and Fusarium-damaged kernels (FDK) under greenhouse and field conditions, respectively. Inconsistent QTL(s) was also detected on chromosome 5BS for disease severity and index using field data. The associations of plant height and number of days to anthesis were negative with disease incidence, severity, index, and deoxynivalenol (DON) accumulation data under field conditions. However, number of days to anthesis was positively correlated with disease severity (greenhouse) and FDK (field). Awnedness had a negative effect on FHB, namely the presence of awns resulted in less disease in the population. Spike threshability also affected FHB so that the hard threshable genotypes represented lower disease. Phylogenetic relationships of putative F. graminearum isolates from different sources were characterized using Tri101 gene sequencing data. Canadian and Iranian isolates clustered in F. graminearum lineage 7 (=F. graminearum sensu stricto) within the F. graminearum clade while the isolates received from CIMMYT, Mexico were placed in F. graminearum lineage 3 (=Fusarium boothii) within the Fg clade or Fusarium cerealis. The PCR assay based on the Tri12 gene revealed the presence of the NIV, 3-ADON, and 15-ADON chemotypes with 15-ADON being the predominant chemotype. While we did not find the NIV chemotype among the Canadian isolates, it was the predominant chemotype among the Iranian isolates. High variation in aggressiveness was observed among and within Fusarium species tested, with the isolates of F. graminearum sensu stricto being the most aggressive and the NIV chemotype being the least aggressive. The interactions between Fusarium isolates and wheat genotypes from different sources were investigated by inoculating isolates of F. graminearum sensu stricto and F. boothii on wheat genotypes. Significant differences were observed among the genotypes inoculated by single isolates. Results also showed significant interactions between Fusarium isolates and wheat genotypes. The F. boothii isolates from CIMMYT produced low disease symptom and infection on wheat genotypes regardless of the origin of the genotypes while F. graminearum sensu stricto isolates from Canada and Iran resulted in higher FHB scores.