Investigation on resistance to scald and covered smut among the selected genotypes of barley under field conditions in Khuzestan, Iran

Scald and covered smut, caused by Rhynchosporium secalis and Ustilago hordei, respectively, are two important diseases of barley in Khuzestan province in the southwest of Iran. The present study was conducted to evaluate the resistance of 100 selected genotypes of barley from different sources to these diseases under field conditions in two research stations of Ahvaz and Shavar in 2019. Evaluation for barley scald leaf disease was performed based on the double digit method 00-99 scale. In the case of covered smut, barley seeds were inoculated by spore suspension of pathogen three times every two days before sowing, and the number and percentage of infected spikes were recorded after the emergence of the disease. According to the results, 6, 15, and 7 genotypes were immune, resistant, and moderately resistant, respectively, and the rest of genotypes were susceptible or moderately susceptible to scald. The barley cultivar Bahman was determined as immune and the cultivars Sahra, Norouz, Lout, Makoui, and Jolgeh were shown to be resistant. In the case of covered smut, 28 genotypes were determined as resistant or moderately resistant and 72 genotypes were shown to be susceptible or moderately susceptible. The barley cultivars Sahra, Goharan, Lout, Valfajr, and Bahman were resistant to the covered smut disease. In this study, the highest percentage of resistance sources for both diseases was related to cold climate and the lowest percentage was related to warm climate.