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Fungal diseases cause significant yield loss to wheat production. Septoria tritici blotch (STB), caused by the ascomycete fungus Zymoseptoria trtici, is one of the major fungal diseases affecting wheat production worldwide. In Ethiopia, STB is a severe problem that causes significant yield loss in high and mid‐altitude wheat‐growing areas. The use of resistant varieties is one of the sustainable disease management strategies, particularly for resource‐poor farmers in developing countries. Two hundred and fifty bread wheat genotypes were evaluated to identify septoria tritici resistant genotypes and estimate the extent of genetic variability for resistance to STB and other economically important traits using alpha lattice design under natural infestation in two STB hotspot environments. Analysis of variance revealed highly significant differences among genotypes, environment, and genotype × environment interaction for all traits measured. The genetic coefficient of variance was lower than the phenotypic coefficient of variance for all traits studied, and both test environments showed the influence of the environment on trait expression. High and moderate heritability values were observed for the septoria disease severity parameters, indicating that the STB resistance trait was less influenced by the environment. The days to heading and plant height were inversely correlated with disease severity. This suggests that genotypes with tall plant height and long maturity period could be resistant to septoria tritici blotch through escape mechanisms. Four of the genotypes, namely, G‐215, G‐255, G‐257, and G‐258, were found to be resistant across all locations. These and other promising genotypes will be used in future breeding programmes to select or develop high‐yielding and STB‐resistant bread wheat genotypes that can be deployed in septoria tritici blotch‐prone areas. Highly susceptible genotypes will also be used as controls for STB resistance breeding programmes. [ABSTRACT FROM AUTHOR]

Wheat is a global staple crop, which contributes 20% of the total dietary proteins and calories. Despite its importance, wheat production and productivity are affected by various biotic and abiotic stresses. Septoria leaf blotch is one of the biotic stresses that decreases production and grain quality. A field survey was conducted in twenty-four districts of Northwestern Ethiopia to figure out its distribution, incidence, severity, and association with agronomic practices and agroecological factors. Logistic regression models were used to figure out associations of the disease intensity with independent variables. The highest mean disease incidence and severity were 90.7 and 46.67%. High severity and incidence were associated with early planting, milk growth stage, and vertisol soil type. This shows that Septoria leaf blotch is a major biotic constraint for the study area. Therefore, effective, and suitable disease management options should be developed to improve the productivity of the crop in Northwestern Ethiopia. [ABSTRACT FROM AUTHOR]