Identification of Stripe Rust (Puccinia striiformis F. sp. Tritici) Resistance in the Ethiopian Wheat Landraces

Abstract

Stripe rust is caused by Puccinia striiformis f. sp. tritici (Pst) is threatening wheat production in Ethiopia. Wheat varieties succumb to new Pst race (s) soon after their release from research centers. The objective of this study was to determine stripe rust resistance in selected Ethiopian wheat landraces obtained from the Ethiopian Institute of Biodiversity (IBCE). In 2017, a total of 197 accessions (152 bread and 45 durum wheat land-races) were exposed to the prevailing stripe rust races in hot spot areas (Kulumsa and Meraro) in Arsi zone of Oromia region. In the second year 2018, only promising landraces 103 (69 bread and 34 durum)) were evaluated both at seedling and adult plant growth stages. The seedling test was conducted in the greenhouse at Kulumsa research center using three Pstraces. In field evaluations, terminal severity (TRS), coefficient of infection (CI), area under disease progress curve (AUDPC), disease progress rate (DPR) and spike infection (SI) were considered. High disease pressure was noted with 100% severity on susceptible entries at both locations and seasons. Highly significant (P<0.001) differences were noted among the landraces for all disease parameters indicated above. Of the 103 landraces, 57 (55%) exhibited lower or equal disease reaction compared to the resistant check (Enkoy) across locations and seasons. Thirty two landraces showed both adult plant and seedling resistance. The 103 Ethiopian wheat landraces that showed field resistance further exposed to three Pst races at seedling stage and 61 exhibited seedling resistance to all races. This study has identified potential sources of seedling and adult plant resistance in the Ethiopian wheat landraces to the prevailing Pst races. Future wheat improvement should focus on utilization of these genetic resources to minimize the re-current outbreak of rust diseases.