Postulation of Seedling Leaf Rust Resistance Genes in Selected Ethiopian and German Bread Wheat Cultivars

Leaf rust caused by the fungus Puccinia triticina Eriks. is one of the most important foliar diseases of wheat (Triticum aestivum L.). Host resistance is the most economical and safest method of controlling the disease. Characterization of the host greatly facilitates the effective utilization of host resistance genes. Gene postulation helps to undertake a quick identification of the probable leaf rust resistance genes (Lr genes) present in a large number of wheat cultivars at a time. The objective of this study was to identify the race-specific Lr-genes present in 36 wheat cultivars from Ethiopia and Germany. Seventy-six wheat genotypes, including 40 near-isogenic lines (NILs), were tested against 31 isolates of P. triticina isolates collected from both countries. Lr-genes Lr1, 2c, 3, 3ka, 9, 10, 14a, 14b, 13, 16, 18, 21, 23, 27+31, 30, 37, and 44 were postulated to be present in the Ethiopian wheat cultivars. Lr genes Lr9, 20, and 21 were present in the German wheat cultivars. The Lr-genes present in some wheat cultivars could not be postulated because of non-matching virulence combinations with any of the NILs. The results of this study show that most of the wheat cultivars tested do not have adequate resistance for leaf rust, indicating the need for incorporating more effective genes into the target wheat cultivars.