High yield stability and susceptibility to stripe rust associate with large yield gaps in rainfed winter wheat

Authors: GIORDANO, NICOLAS - Kansas State University; SADRAS, VICTOR - South Australian Research And Development Institute; Guttieri, Mary; HEFLEY, TREVOR - Kansas State University; ROMERO SOLER, JORGE - Kansas State University; NEELY, CLARK - Washington State University; EDWARDS, JEFFREY - University Of Arkansas; SILVA, AMANDA DE OLIVE - Oklahoma State University; FRITZ, ALLAN - Kansas State University; LOLLATO, ROMULO - Kansas State University

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2025
Publication Date: 9/2/2025
Citation: Giordano, N., Sadras, V.O., Guttieri, M.J., Hefley, T.J., Romero Soler, J.A., Neely, C., Edwards, J.T., Silva, A.I., Fritz, A.K., Lollato, R.P. 2025. High yield stability and susceptibility to stripe rust associate with large yield gaps in rainfed winter wheat. Field Crops Research. 333. Article 110118. https://doi.org/10.1016/j.fcr.2025.110118.
DOI: https://doi.org/10.1016/j.fcr.2025.110118

Interpretive Summary: The gap between actual wheat grain yield and the potential yield, given water availability, is described as the 'yield gap.' This yield gap is an economic opportunity lost for wheat producers. Both wheat genetic stripe rust disease resistance and wheat cultivar ability to respond to favorable environmental conditions can play roles in reducing the wheat yield gap. Data for grain yield and stripe rust severity in 21 growing environments, with and without fungicide application, and between 20 and 55 cultivars per trial, was used to calculate yield gaps. In growing environments conducive to developing stripe rust (cool, wet), both yield responsiveness and stripe rust resistance were important to reduce yield gaps. Stripe rust resistance was not detrimental to yield in the absence of the stripe rust disease. The implications of this work are that breeders can develop cultivars with high yield responsiveness and stripe rust resistance that are adapted to regions where stripe rust is present but uncommon, such as western Great Plains. Also, forecasting models to quantify the benefits of a fungicide application under varying environments and disease resistance can be of benefit to wheat producers and consumers by optimizing the use of fungicides to control stripe rust.

Technical Abstract: Context Narrowing yield gaps, i.e. the difference between water-limited yield potential and actual yield, is fundamental for food security. Phenotypic plasticity of grain yield and resistance to stripe rust (Puccinia striiformis f. sp. tritici) have been analyzed independently, but their combined contribution to yield gaps in wheat (Triticum aestivum L.) is uncertain. Hypotheses This study tested three hypotheses. First, yield gap increases with decreasing yield plasticity, i.e. there is a tradeoff between yield stability and yield gap. Second, resistant phenotypes have smaller yield gaps under conditions favoring stripe rust development. Third, absent of conditions favorable to disease development or presence of crop protection, responses to stripe rust resistance would depend on whether there is or not a metabolic cost of stripe rust resistance. By exploring these hypotheses, we aim to understand trade-offs and synergies between stripe rust resistance and yield phenotypic plasticity under varying management and environment. Method Grain yield, and stripe rust ratings were obtained from a factorial experiment comparing 20-55 cultivars under two management intensities, one reflecting standard grower practices in the region (i.e., enough N for a yield goal of 4 Mg ha-1 and no fungicide applied), and a second with a reasonable level of management intensification (i.e., an additional 45 kg N ha-1, one fungicide application at jointing and a second at heading) in 21 location-years in the southern Great Plains of the US. We estimated cultivar-specific yield phenotypic plasticity (i.e., the inverse of yield stability) as the ratio between the yield variance of a given genotype and the total yield variance in the dataset. Water-limited yield potential was estimated using quantile regression, and used to derive yield gaps. Results Cultivars with high yield phenotypic plasticity (less stable yield) had smaller yield gaps in environments with high water-limited yield potential. Combining the addition of N and fungicide with cultivars with high yield plasticity could narrow yield gap regardless of environmental potential. Under conditions favorable for disease, stripe rust resistance narrowed yield gaps, particularly where disease chemical control was absent or ineffective. The null yield difference between stripe rust resistant and susceptible phenotypes when protected with foliar fungicides reflects there is no cost of disease resistance. Conclusion Both yield stability and stripe rust susceptibility increase the magnitude of yield gaps in winter wheat regardless of environment yield potential and conditions conducive to stripe rust development. Implications When disease is absent, stripe rust resistance does not have a yield penalty, suggesting that breeders can develop cultivars with high yield plasticity and stripe rust resistance adapted to environments where stripe rust is present but uncommon, such as western Great Plains. Developing forecasting models to quantify the economic benefits of crop protection under varying environments and disease resistance can contribute to: (i) target crop protection to conditions where positive economic benefits are more likely and (ii) reduce environmental footprint from fungicide use.