(i) Project aim(s):
To identify the cause of daffodil rust
(ii) Project objective(s):
1 Extend the current two-year project to a third year in order to complete observations on the existing trial plots over the typical three-year-down growing cycle used in daffodil growing:
1.1 Complete observations on the effect of the soil/water environment and related factors on the incidence and severity of daffodil rust
1.2 Obtain further analyses of nutrients in soil and plant tissue associated with rust-affected and ‘healthy’ plots
1.3 Continue pathogen testing of rust-affected and ‘healthy’ stems
2 Investigate any association of daffodil rust with virus infection by RNA extraction and sequencing of rust-affected and ‘healthy’ stem tissue, using samples previously collected in the project and stored at -70°C
3 Determine the earliest date that daffodil rust symptoms appear by examining the above- and below-ground parts of stems at intervals from before bulb sprouting until flowering; this will inform us on the time-scale of rust development
4 Survey commercial cut-flower samples to discover whether mild daffodil rust symptoms are ubiquitous in a rust-prone and a non-rust-prone cultivar; this is basic information that will help us understand daffodil rust
5 Build on the results of the original project to inform the daffodil industry on the cause of daffodil rust and assist in formulating a protocol for its control through remedial treatments, avoidance strategies and risk management opportunities, using presentations at grower meetings, articles and a fact-sheet; if appropriate, facilitate discussions with science specialists on further research needs
Together, objectives 1 and 5 form a package. This package and objectives 2 to 4 are not interdependent, but much more would be added to our understanding of daffodil rust if all objectives were included.
The project extension would be based on work carried out in one year, and the overall project would be based on studying a single three-year crop cycle in one region of the UK, so it is possible the findings may not be truly representative because of weather, local factors or year-to-year variation.
Conditions beyond the contractor’s control, such as unusual weather, serious pest or disease problems, or material changes within the bulb industry, could affect the process of obtaining representative results. The sporadic nature of daffodil rust means that in some years the disorder is absent or occurs at a very low level.