Identification and validation of SNP markers for Fusarium head blight resistance in wheat

Abstract

Fusarium graminearum is a fungal pathogen known to cause Fusarium head blight, and has greatly affected the yield and grain quality of Norwegian wheat. The most cost efficient way to reduce infection and severity of the disease is to develop new resistant cultivars. Fusarium resistance is a complex trait, caused by many medium to small effect genes. Genome wide association mapping can be a powerful tool to map these genes. In this thesis, we use marker from the 90K SNP array, along with phenotypic data from a core collection of 405 MASBASIS spring and winter wheat lines from 2013-2015. The population consists of lines from eight different subpopulation with different geographical origin and habitat. The traits that are being assessed are mainly fusarium head blight severity, deoxynivalenol content, and anther extrusion. Plant height and earliness are also being noted due to its close relationship to fusarium head blight infection. All traits showed significant markers around previously documented QTLs, indicating that the markers for undocumented QTLs that were discovered in this associating mapping might be significant to. Heritabilities for each trait were calculated using analysis of variance, which showed that observed variance resulting genetics were lower for FHB than for DON. This indicates that FHB is more affected by environmental effects and assessment errors. DON could therefore be considered a more accurate parameter than FHB, which shows in both the heritability and number of valid significant markers found. The goal of this thesis is to map the resistance QTLs of the Norwegian breeding material, and validate new QTLs that can be used marker assisted selection for the breeding company Graminor in Norway.