Evaluation of the seedling and full-grown plant resistance of wheat genotypes to the yellow rust dominant pathotype in Kermanshah Province

Responses of twenty four selected wheat genotypes including commercial cultivars and isogenic lines against the yellow rust (Puccinia striiformis f. sp. tritici; 6E158A pathotype) were evaluated in Kermanshah province, Iran. Infection type and disease severity as the resistance characteristics were studied in greenhouse and field conditions for seedlings and adult plants respectively. Cluster analysis of seedling stages based on infection type indicated that 8% of the genotypes had probably resistant genes with minor while major effects and other genotypes were controlled by major effect genes. Area under disease progress curve (AUDPC) and relative area under disease progress curve (rAUDPC) criteria were calculated for wheat genotypes in adult plants stages. Cluster analysis using infection type of the first leaf data showed that 29% of the genotypes were susceptible in seedling and adult plant stages; 8% of genotypes were sensitive in the seedling stage but resistant in the adult stage. Additionally, it was found that 25% of the genotypes were resistant in whole periods of growth. High significant correlation (P≤0.01) was calculated for the infection type of the first leaf and two other parameters included AUDPC of flag leaf and infection coefficient.