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Identification of Fusarium resistance traits in UK oat varieties

Stancic, T. (2016) Identification of Fusarium resistance traits in UK oat varieties. Doctoral thesis, Harper Adams University.

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Abstract

Previous studies identified that UK oats are routinely infected by Fusarium langsethiae and this infection can result in high levels of the fusarium mycotoxins, HT2 and T2 on harvested oat grains. The European Commission are currently considering legislative limits for the combined concentration of these mycotoxins (HT2+T2). An indicative limit of 1000 μg kg-1 recommended by the European Commission is exceeded, on average, in 18% of UK oat samples. The aim of this PhD project was to understand the variation in resistance of UK oat varieties to F. langsethiae. In previous studies conducted across the UK it was identified that all winter oat variety trials had higher levels of HT2+T2 mycotoxins compared to the spring variety trials but it was not known whether the difference observed was due to agronomic (i.e. sowing date) or genetic variations. To test the hypothesis that the differences observed were not due to agronomy, experiments were conducted with winter and spring varieties sown together in both autumn and spring sown experiments. Results indicated that some winter varieties had consistently higher HT2+T2 irrespective of sowing date, and are therefore genetically more susceptible to F. langsethiae infection. It was also previously observed that grains of naked oat varieties had lower levels of HT2+T2 at harvest but it was not clear how naked and conventional husked oat crops compared before harvest. Results from this study identified that some naked oat varieties have high HT2+T2 levels before harvest and as such these varieties have high susceptibility to F. langsethiae. In previous studies high concentrations of HT2+T2 were detected on grains of dwarf varieties compared to conventional height varieties. To test the hypothesis that the difference observed between dwarf and varieties of a conventional height was not due to morphological trait of crop height experiments were conducted with a dwarf and tall variety with height further manipulated by a iii range of PGR doses. To test the same hypothesis of whether crop height is a susceptibility trait, experiments at the University of Aberystwyth with a mapping population developed from a cross between short and tall winter oat varieties were used for the identification of QTL for resistance and to determine genetic linkage with agronomic traits such as height. Results identified that height per se is a resistance factor, but is only one of many, or there is close genetic linkage between the dwarf gene and a susceptibility QTL. As currently our knowledge of factors facilitating Fusarium resistance in oat varieties is limited, experiments with artificial inoculation of the model cereal Brachypodium with F. langsethiae were performed as part of this project. Results indicated that Brachypodium is a host for F. langsethiae and produces typical head blight symptoms after infection. Results from this project have identified differences in F. langsethiae resistance within UK oat varieties and identified potential QTL for use in marker assisted breeding.

Item Type: Thesis (Doctoral)
Divisions: Crop and Environment Sciences
Depositing User: Ms Kath Osborn
Date Deposited: 21 Aug 2018 15:35
Last Modified: 22 Aug 2018 13:32
URI: http://hau.collections.crest.ac.uk/id/eprint/17313

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