Source: KANSAS STATE UNIV submitted to NRP
PREDICTING THE RISK OF YIELD LOSSES CAUSED BY HEAT TOLERANT STRAINS OF THE WHEAT STRIPE RUST PATHOGEN
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
Reporting Frequency
Annual
Accession No.
1032286
Grant No.
2024-68008-42645
Cumulative Award Amt.
$300,000.00
Proposal No.
2023-09573
Multistate No.
(N/A)
Project Start Date
Jul 1, 2024
Project End Date
Jun 30, 2026
Grant Year
2024
Program Code
[A1701]- Critical Agricultural Research and Extension: CARE
Recipient Organization
KANSAS STATE UNIV
(N/A)
MANHATTAN,KS 66506
Performing Department
(N/A)
Non Technical Summary
Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, has emerged as a threat to wheat production in the central Great Plains region of the United States. Over the past 20 years, the frequency of stripe rust epidemics continues has increased with statewide yield losses often exceeding $75 Million in Kansas annually. Recent field observations and preliminary experiments indicate that populations of P. striiformis f. sp. tritici are continuing to adapt to the wheat production systems and environment of the Great Plains. These adaptations include the emergence of strains of P. striiformis f. sp. tritici that recover more rapidly from periods of heat stress than isolates collected just a decade ago. In this proposal, we propose integrated research and extension projects that address this threat to wheat production in the United States. The objectives of these projects are to: 1. Evaluate of the variation of heat stress tolerance in a broader sample of historical and contemporary isolates of P. striiformis f.sp. tritici; 2. Develop predictive models describing the probability that high temperatures will suppress stripe rust development and improve the real-time prediction of disease severity; 3. Deploy the predictive models via web-based tools used to evaluate the risk of multiple threats to wheat production in the region; 4. Verify model predictions and communicate the risk of severe stripe rust based on disease forecasting models and observations of disease activity in the Kansas. The research and extension approaches to accomplishing these objectives will include experiments in controlled environments to quantify the response of P. striiformis f.sp. tritici isolates representing both historical and contemporary populations in the state. The isolates tested in these experiments will include those collected between 1991- 2023 as well as, contemporary isolates sampled from research plots and commercial fields during the duration of the study. The results for these experiments will inform temperature thresholds used in the modeling of potentially suppressive nature of heat stress events on stripe rust development. Predictive models estimating the probability that heat stress events will suppress stripe rust development will be based on historical datasets of observations from replicated research plots and regional disease loss estimates collected between 2000 - 2023. The analytical approach used to develop the models will include a combination of regression and machine learning techniques of variable selection, and model fitting. The resulting models will be deployed via a suite of web-based tools known as the "Kansas Wheat Dashboard" that is currently used by extension specialists in Kansas. This dashboard uses hourly weather observations gathered by the National Weather Service and agricultural weather networks to produce maps of disease risk, as well as, multiple abiotic threats to wheat production in Kansas. The model predictions regarding the suppression of stripe rust will be verified using observations collected from replicated research plots and commercial wheat fields throughout the states. The model results and observations of disease will be used to communicate the risk of severe stripe rust and the need for wheat growers to protect their crops with timely fungicide applications. These communications will utilize maps from the Kansas Wheat Dashboard and provide recommendations via electronic newsletters, social media posts, and other established extension resources that reach thousands of growers each week.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21215401170100%
Goals / Objectives
In this proposal, we propose integrated research and Extension projects that address this threat to wheat production in the United States. The goals of these projects are to: 1. Evaluate of the variation of heat stress tolerance in a broader sample of historical and contemporary isolates of P. striiformis f.sp. tritici; 2. Develop predictive models describing the probability that high temperatures will suppress stripe rust development and improve the real-time prediction of disease severity; 3. Deploy the predictive models via web-based tools used to evaluate the risk of multiple threats to wheat production in the region; 4. Verify model predictions and communicate the risk of severe stripe rust based on disease forecasting models and observations of disease activity in the Kansas through targeted extension efforts.
Project Methods
The research and extension approaches to accomplishing these objectives will include experiments in controlled environments to quantify the response of P. striiformis f.sp. tritici isolates representing both historical and contemporary populations in the state. The isolates tested in these experiments will include those collected between 1991- 2023 as well as, contemporary isolates sampled from research plots and commercial fields during the duration of the study. The results for these experiments will inform temperature thresholds used in the modeling of potentially suppressive nature of heat stress events on stripe rust development. Predictive models estimating the probability that heat stress events will suppress stripe rust development will be based on historical datasets of observations from replicated research plots and regional disease loss estimates collected between 2000 - 2023. The analytical approach used to develop the models will include a combination of regression and machine learning techniques of variable selection, and model fitting. The resulting models will be deployed via a suite of web-based tools known as the "Kansas Wheat Dashboard" that is currently used by extension specialists in Kansas. This dashboard uses hourly weather observations gathered by the National Weather Service and agricultural weather networks to produce maps of disease risk, as well as, multiple abiotic threats to wheat production in Kansas. The model predictions regarding the suppression of stripe rust will be verified using observations collected from replicated research plots and commercial wheat fields throughout the states. The model results and observations of disease will be used to communicate the risk of severe stripe rust and the need for wheat growers to protect their crops with timely fungicide applications. These communications will utilize maps from the Kansas Wheat Dashboard and provide recommendations via electronic newsletters, social media posts, and other established extension resources that reach thousands of growers each week.

Progress 07/01/24 to 06/30/25

Outputs
Target Audience:The target audience for this project includes wheat farmers, crop consultants and agricultural industry representatives. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have hired a Ph.D. level graduate student to assist with this project. This individual is responsible for the growth chamber experiments, and model development. The project also provides professional development opportunities for two other graduate students that help with field experiments evaluating the application of disease forecasting models. How have the results been disseminated to communities of interest?Maps displaying the likelihood that heat stress events will suppress a developing stripe rust epidemic were incorporated into a suite of web-based tools we call the Wheat Dashboard. These models are currently being evaluated by researchers and extension specialists in KS and other key wheat producing states. Implementing these models in the wheat dashboard positions us to communicate directly to wheat growers during the 2025-2026 growing season. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period we will explore additional experiments evaluating the influence of heat stress on the development of stripe rust and pathogen reproduction. This includes efforts to develop a more rapid assessment of isolate heat stress tolerance. We will continue to evaluate and refine models describing the suppressive effects of heat stress on stripe rust development in field environments. This includes model development and testing on an expanded dataset of more than 300 observations collected over the past 18 years. Candidate models will be implemented in the Wheat Dashboard and tested for potential merits to help growers make practical fungicide decisions. These models will be incorporated into field experiments evaluating the potential role of this information in helping wheat growers make timely fungicide decisions.

Impacts
What was accomplished under these goals? During the first year of this project we made progress on multiple project objectives. Objective 1: Progress on this objective includes collecting additional isolates of P. striiformis f. sp. triticifor evaluation for heat stress tolerance. These isolates were purified and increased for use in experiments quantifying isolate response to heat stress. We then conducted 6 replicate experiments focused on comparing the response of pathogen isolates to heat stress. These experiments including 18 isolates collected between 2010 - 2024. Two stripe rust susceptible wheat varieties were inoculated with each isolate and groups of plants exposed to either a cool temperature regime that was ideal for stripe rust development or and temperature regime including 7 days of heat stress (low of 22 C and high of 35 C). Disease development and pathogen reproduction was then visually evaluated every 3 days that the disease developed on the plants for the next 3 weeks. The results indicate that many of the isolates collected after 2016 were able to recover from periods of heat stress more quickly than isolates collected just a decade ago. However, heat stress still does slow progression of the disease and reproduction of the pathogen. Objective 2: We developed preliminary models predicting the likelihood that heat stress events will suppress stripe rust development in commercial wheat production in KS. These models were based on field observations from replicated research plots and commercial fields collected between 2008 - 2024 (n=104). The results of growth chamber experiments (objective 1) were used to design variables representing the current hypotheses about the potential role of heat stress in suppressing stripe rust development. Modeling results identified that the duration of temperature greater than 25 C was strongly associated with the suppression of stripe rust epidemic's in KS. These models correctly distinguished years and locations with low or high levels of disease with nearly 80% accuracy. Objective 3: We integrated models estimating the likelihood that high temperatures will suppress a developing stripe rust epidemic in the KS Wheat Dashboard. These web-based tools provide daily estimates of disease risk for stripe rust in Kansas and throughout the region. We are currently testing the prototype heat stress models in the wheat dashboard and plans are in place to launch these models for wheat grower evaluation during the 2026 growing season. Objective 4: Replicated research plots were established at 5 locations during the 2024-2025 wheat growing season. These plots included treatments designed to help evaluate different approaches to applying the predictive models for wheat stripe rust. The model timed applications were compared to industry standard applications based crop growth stage alone. Disease severity was evaluated during the milk stages of grain development and plots harvested with a research combine at maturity.The overall severity of stripe rust was low during the 2024-2025 growing season, however, moderate levels of disease developed at two of the research locations. We are currently processing the yield results for setting up the treatment comparisons.

Publications

  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2025 Citation: Vicentin, E., Andersen Onofre, K. and De Wolf, E. 2025. Diminishing effects of heat stress on the development of stripe rust (Puccina striiformis f. sp. tritici) on winter wheat. National Plant Health Meeting, Honolulu HI, Aug. 3-5, 2025
  • Type: Conference Papers and Presentations Status: Published Year Published: 2025 Citation: De Wolf, E. 2025. Development and application of predictive models for wheat diseases in the US. Annual Meeting of the National Predictive Model Initiative, Pensacola Beech, FL, March 27-28, 2025.