Evaluation of tolerance to leaf rust disease in some selected bread wheat genotypes

Tolerance to diseases is, the plant's ability to produce good yield even when the plant is infected by pathogen. In fact tolerant plants are susceptible to the pathogen but not destroyed by pathogens and generally little damage is caused on the plant. In this study, the tolerance of 20 wheat genotypes was evaluated against leaf rust. The effect of leaf rust on yield was evaluated in severe disease (stress) conditions and in protected from disease conditions (the controls) in Ahvaz area. The mean percentage of yield reduction caused by leaf rust was 25.2% over all genotypes. The range of yield loss was varied from 7 to 46 percent. The lowest yield loss due to the leaf rust, ranged from 6 to 16% in Shirodei, Aflak, Sirvan, Shiraz, Inia and Ofogh cultivars indicating their highest yield stability to leaf rust. Based on these data, the highest yield loss ranged from 30 to 50% in Bolany, Neyshabur, Toos, Alvand, Roshan, Star, Shahriar and Veerynak cultivars with the lowest yield stability. The cultivars Kavir, Shahriar, Roshan, Toos, Veerynak, Bahar, Bolany, Alvand and Ofogh were susceptible to leaf rust. Ofogh and Bahar with 16.52% and 21.8% yield loss respectively, were the most tolerant cultivars of this group.