Phenotypic characterization of the Hordeum bulbosum derived leaf rust resistance genes Rph22 and Rph26 in barley
Xiaohui Yu1, Seona Casonato1, Eirian Jones1
1Faculty of Agriculture and Life Sciences, Department of Pest-Management and Conservation, Lincoln University, Lincoln, Canterbury, New Zealand.
Journal of Applied Microbiology
|July 11, 2022
Summary
Barley introgression lines carrying Rph22 and Rph26 genes show increasing resistance to leaf rust (Puccinia hordei) as plants mature. These genes confer adult plant resistance (APR), crucial for future breeding programs.
Area of Science:
- Plant Pathology
- Genetics
- Crop Science
Background:
- Two barley introgression lines (ILs), 182Q20 and 200A12, possess introgressed segments from Hordeum bulbosum.
- These ILs exhibit seedling resistance to Puccinia hordei, potentially due to resistance genes Rph22 and Rph26.
Purpose of the Study:
- To characterize the phenotypic responses of Rph22 and Rph26 against P. hordei across different barley developmental stages.
- To understand the effectiveness and expression of these resistance genes throughout plant growth.
Main Methods:
- Visual assessment and fungal biomass determination of ILs and barley cultivars against P. hordei.
- Evaluation at seedling, tillering, stem elongation, and booting stages.
Main Results:
- Plants with Rph22 or Rph26 displayed progressively stronger resistance as they developed.
- Partial resistance was observed at the seedling stage, transitioning to adult plant resistance (APR) by the booting stage.
- A clear shift in resistance type occurred during the tillering stage.
Conclusions:
- Rph22 and Rph26, originating from H. bulbosum, exhibit characteristic APR phenotypes against P. hordei.
- These findings offer valuable insights for barley breeding programs aiming to manage leaf rust using non-host genetic resources.
