Pathogenicity of Puccinia striiformis f. sp. tritici and quantitative traits on bread wheat landraces in Ethiopia

Abstract

AbstractBread wheat (Triticum aestivum L.) is severely affected by stripe rust caused by Puccinia striiformis Westend. f. sp. tritici (Pst). This study was conducted to investigate pathogenicity of Pst isolates to bread wheat landraces grown in Ethiopia, establish stripe rust yield loss models and estimate variability in bread wheat quantitative traits. A greenhouse pot experiment was setup to assess seedling stage responses of landraces to Pst and a field study was conducted for adult plant stage evaluation. Among dominant isolates of Pst, Kubsa was the most virulent. Apart from the detection of resistance at the seedling stage study, a broad range of adult‐stage resistance was also observed which can confer durable resistance. Among single‐point models, the onset of severe infection at the development of heading stage causes significant yield loss by stripe rust. The integral yield loss model predicted a strong negative linear relationship between agronomic traits and stripe rust. Hierarchical analysis revealed the presence of three distinct clusters of bread wheat landraces, each forming different stripe rust resistance groups. With the exception of the harvest index and the growth stage parameter of days to heading, all agronomic traits were significantly different for the various landraces. This suggests the presence of diverse genetic resources, which might have also led to different responses to the stripe rust in these materials. This work clarifies the many ways in which landraces of bread wheat react to Pst infection, revealing a range of resistance mechanisms that can be used for efficient disease management.