Project Number: 8042-21000-023-013-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Sep 15, 2022
End Date: Sep 14, 2024
Fruit rot is a complex disease system in cranberry that can cause severe crop loss in the major production regions. A better understanding of the fungi that cause the disease, the contribution from environment, the nature of genetic resistance in cranberry, and tools for predicting the outbreak of disease would help stakeholders such as growers and processors implement improved management practices that would deliver higher profits and high-quality fruit to consumers with reduced environmental impact. Objective 1. Characterization of cranberry fruit rot fungi Objective 2. Evaluate environmental contributions to fruit rot expression Objective 3. Develop systems to deploy genetic resources for optimized fruit rot management Objective 4. Develop integrated models to predict fruit rot epidemics
Objective 1: 1) Characterize fruit rot fungal populations in different regions utilizing spore trapping methods and molecular diagnostics, and 2) Investigate reductions in fungicide sensitivity for the predominant fungal species in each region utilizing a bioassay developed by Co-PI Oudemans. The fungicide azoxystrobin is high risk and currently presents the greatest threat to fungicide resistance development. Objective 2: 1) Collect environmental data from the major production regions and correlate it with fruit rot expression to identify the most explanatory environmental factors; 2) Environmental stress treatments (ex. elevated temperatures, high humidity, variable light radiation, water stress, variable nitrogen fertilization rates) will be applied under controlled conditions (i.e., growth chambers) and in the field and correlated to fruit rot incidence. Objective 3: 1) Field trials established in locations in North America will be used to compare productivity, disease susceptibility and stress tolerance under different climatic conditions. 2) Comparison of genotypes by measuring stress responses under common field plot conditions (i.e. carbon discrimination method); 3) Evaluation of biochemical, hormonal changes and other anatomical characteristics (such as wax layer, stomate number, ripening seasonality) contributing to susceptibility or resistance to fruit rot disease development will enhance selection of stress tolerant varieties. Objective 4: 1) Informed by the results of experiments in Objectives 1-3, we will develop in-season fruit rot risk prediction models. These models will rely on logistic regression and include predictors based on relative cultivar resistance and selection of critical weather and soil variables to maximize predictive ability. Models will be trained and tested using historical fruit rot incidence data and local weather/soil conditions from multiple cranberry growing regions.