CHARACTERIZATION OF ETHIOPIAN DURUM WHEAT LANDRACES FOR RESISTANCE TO STRIPE RUST DISEASE AND AGRONOMIC TRAITS

Abstract

The research was conducted to identify Ethiopian durum wheat accessions possessing effective stripe rust resistance genes and estimate the genetic variation for agronomic traits. The study investigated 142 accessions and two improved cultivars in greenhouse and field conditions. Six Puccinia striiformis f.sp. tritici (Pst) isolates were employed to evaluate the accessions at the seedling stage in the greenhouse. The field trial was conducted using an alpha lattice design with two replications. The study highlighted the presence of significant variation among accessions. In the seedling test, 26.1% of accessions showed resistance, 35.91% intermediate, and 38.0% susceptible reactions to Pst isolates. The field response of the accessions to Pst infection indicated that 18.3% had low terminal disease severity (TDS) scores, while 18.7% had average coefficient of infection (ACI) values < 20%; and 26.8% exhibited AUDPC values < 500. A low disease progress rate with infection values ≤ 1 was observed on 4.2% of the accessions. The ANOVA computed for all agronomic traits showed highly significant differences, indicating the presence of variation among accessions. The H²_b estimate ranged from 8% (harvest index) to 92% (above-ground biomass). Genetic advance as a percent of the mean varied from 3% for days to maturity to 490% for above-ground biomass. Multivariate analysis grouped the 144 durum wheat genotypes into six clusters, while the first five principal components explained 73.1% of the total variance. This study has demonstrated the presence of diverse genetic resources of durum wheat accessions, among which 14 landraces showed high levels of adult plant stripe rust resistance.