Adult-plant resistance and appropriate method of reaction determination to leaf blotch (Zymoseptoria tritici) in wheat genotypes at a hot spot location in Ethiopia

Leaf blotch caused by the fungal pathogen Zymoseptoria tritici is a significant wheat foliar disease. In the current study, the reactions of 100 wheat genotypes to leaf blotch were evaluated under natural conditions in Ethiopia in the 2022/2023 growing seasons. Field trials were conducted using a simple lattice design. The first (Eyal et al. class, and Eyal and Brown reactions) and second (Sharma and Duveiller) methods were evaluated to determine the reaction of genotype’s. The relationship between independent and dependent variables was analyzed using the Pearson correlation in ellipses predictor at a p value of 0.05 and 0.01. Logistic and Gompertz models were used for disease rate analysis. Grain yield was measured in four center rows (1.6 m2), and the results were converted to t ha−1. Out of one hundred genotypes evaluated, 80% were moderately susceptible, 15% were susceptible, 2% were moderately resistant, and 3% were resistant. Lines such as 21 Elite (087), 41ESWYT (028), 54IBWSN (035), and the cultivar Danda’a were susceptible. The highest grain yields, 2.8 t ha−1 for cultivar HB# Balcha and 2.4 t ha−1 for genotype 43ESWYT (099), were recorded. The lines 21SHPYT (046), 41ESWYT (046), and 41ESWYT (099) were resistant; therefore, they can be used for crossing and variety development scheme. A significant (r=-0.07) negative correlation between plant height and leaf blotch severity indicated that wheat breeders should consider these two variables in the breeding scheme to regulate the disease severity. The first method is very important to determine disease reaction determination.