Evaluation the resistance of some CIMMYT wheat lines to tan spot disease

Tan spot disease caused by Pyrenophora tritici-repentis is a destructive disease in wheat production areas around the world. The disease has a high prevalence and distribution in the Golestan, Mazandaran, and northern regions of Ardabil province. Due to the lack of suitable resistant varieties in Iran, the damage caused by the disease is high. In this study, the evaluation of 50 wheat lines resistance belonging to the 9HLBSN treasury of the International Maize and Wheat Research Center (CIMMYT) was investigated using race1 of the pathogen. By inducing the fungal isolates to produce abundant conidia, the infection was established in the wheat seedlings through inoculation of the suspension of fungal conidia. The results of this study demonstrated that lines number 1, 17, 18, 22, 25, 29, 33, 34, 35, 36, 37, 38, 44, 45, and 47 had a susceptible reaction, and other lines which included 70% of investigated lines, were resistant. In addition, the mean disease index in different lines was calculated and compared. In terms of the mean disease index on the evaluated lines, 13 groups were obtained, which had 8, 8, 8, 4, 3, 5, 12, 23, 24, 28, 28, 26, and 22 members, respectively. Considering the susceptibility of most of the country's commercial cultivars to this disease, the resistant lines obtained in this study are good sources of resistance to be used in the breeding programs of wheat.