Performance and disease resistance of faba bean (Vicia faba L.) varieties under chocolate spot and rust pressure in the Bale Highlands of Ethiopia

Field evaluation of twenty-one faba bean ( Vicia faba L.) varieties was conducted across three highland environments of Bale, Ethiopia, to assess grain yield performance and resistance to chocolate spot and rust diseases under natural epidemic conditions. A randomized complete block design with three replications was employed, and key agronomic and disease-related traits were analyzed. Combined ANOVA revealed highly significant ( p < 0.01) genotype and genotype × environment interaction effects, indicating substantial genetic variability and differential adaptation among genotypes. Grain yield ranged from 2218.75 to 5195.62 kg ha⁻¹, with Moti and Tesfa exhibiting clear yield superiority across environments. Yield performance showed positive associations with leaf area index, pod traits, and harvest index, while disease severity indices were negatively correlated with yield, confirming the impact of disease pressure on productivity. Moderate to high genotypic and phenotypic coefficients of variation, coupled with heritability estimates up to 75.9%, suggest strong genetic control for key agronomic traits. Multivariate analyses further revealed distinct genetic groupings, supporting the presence of exploitable diversity. Notably, Moti and Tesfa combined high yield potential with moderate resistance to both chocolate spot and rust, demonstrating stable adaptation demonstrating superior adaptability across test environments and under dual disease pressure. These findings provide strong evidence for selecting integrated yield–disease resilience traits and contribute to the development of climate-resilient and disease-tolerant faba bean cultivars for Ethiopian highland agro-ecologies.