Identification of Stable and Rust-Resistant Bread Wheat Genotypes through Multi-Environment Trial Analysis in Ethiopia

Abstract

Bread wheat (Triticum aestivum L., 2n = 6x = 42) is a globally important crop, with projected production of nearly 793 million metric tons in 2024/2025. In Ethiopia, yields have increased from 1.18 t/ha in 2000 to 3.1 t/ha by 2022, yet production remains threatened by rust diseases and other stresses. The objective of this study is to identify stable and rust-resistant bread wheat genotypes through multi-environment trial analysis in Ethiopia. This study evaluated 378 genotypes from the national breeding pipeline across multiple locations in 2024 to identify high-yielding, rust-resistant, and stable lines. Genotypes were tested in stage-gated trials: 318 in the Observation Nursery, 37 in the Preliminary Variety Trial, 16 in the 1st-Year National Variety Trial, and 5 in the 2nd-Year National Variety Trial, with Boru and Deka as checks. Multi-environment trial analyses using linear mixed models revealed contrasting stability and yield performance. Among the tested genotypes, EBW202020 and EBW202473 exhibited moderate susceptibility to stem rust, with EBW202020 further constrained by poor grain yield stability across nine clustered environments. EBW202471 showed consistent superiority with moderate fluctuations, EBW202472 exhibited high responsiveness but poor stability, and EBW202473 performed stably, though not always at the highest yield. Based on combined performance, EBW202471, EBW202472, and EBW202473 were identified as promising candidates for advancement.