Location: Crop Production and Protection
Project Number: 0500-00102-001-054-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 1, 2024
End Date: May 31, 2025
Objective:
Additional information about the role of environment in pathogen survival, movement of inoculum and disease progress is essential to the development of robust predictive models of rust diseases and Parastagonospora leaf blotch (PLB). Therefore, this year of the wheat Predictive Model Tool Initiative will focus on the following objectives: 1) Develop predictive models based on databases of past disease epidemics in the U.S.; 2) Quantify the relationship between pathogen inoculum density, disease development, and weather in small plot trials; and 3) Quantify the relationships between pathogen inoculum, disease development and weather in commercial fields.
Approach:
To achieve objective 1, curated disease observations will be coupled with weather and cropping system data. Weather information will include ground-based weather stations maintained by a federal agency and universities, as well as georeferenced weather products maintained by the project cooperators. Preliminary models of disease risk based on historical observations of epidemics will be developed. The most useful variables will be used to develop preliminary models using linear regression, logistic regression and machine learning analytical approaches. The observations collected in replicated research plots and commercial fields will be used to evaluate model performance before public deployment (see objectives 2 and 3 below). To achieve objective 2, experiments will be established on the university's research site located near Princeton, KY in a field previously planted to a non-host crop. In the selected field, three residue blocks will be established representing <20, 50-60, and >80% residue cover. Each residue treatment will be established by spreading different amounts of previously baled wheat straw from fields with disease incidence in the previous season, to accomplish the desired levels of surface cover. In each residue block, four plots will be planted with four widely grown commercial wheat varieties, two different varieties that are “equally” susceptible to stripe rust; and two varieties that are resistant to the current stripe rust races but susceptible to PLB. These varieties will be planted on the same date but have different maturities (early- and late-maturing) to increase the number of environments sampled each year. Plots will not be treated with a foliar fungicide. Wheat stubble will be collected at 20 equally spaced points along the “W” path (5 samples per transect) and bulked into a single composite sample per residue block. Samples will be air-dried as needed, weighed, and shipped, to the cooperator. Every 24 hours, sampled air particles will be collected and sent to the cooperator's laboratory for DNA extraction and qPCR analysis. The cooperator will develop standardized protocols to quantify DNA of each pathogen in each spore sample. Leaf spot diseases and rust will be rated visually on a weekly basis. To achieve objective 3, a total of 20 production wheat fields will be selected that consist of any one or more of the following 1) fields planted to wheat the previous season, 2) fields planted to wheat two seasons prior, 3) fields adjacent to a field that was planted to wheat the previous season, and 4) fields in which state variety performance trials are established. The amount of wheat residue on the soil surface will be estimated in each field in the fall and spring. Wheat stubble and airborne spores will be collected and processed as described under objective 2. Leaf spot diseases and rust intensity will be rated in each field.
