كليدواژه :
resistance , barley , cultivars , barley stripe , جو , كشاورزي , لكه قهوه اي نواري جو , منطقه ورامين
چكيده لاتين :
Barley stripe is a common disease of barley where the crop is grown. The mean percentage of infected barley fields during 2000 and 2001 was estimated 5.17 ± 2.5 and 3.67 ± 2.38, respectively in Varamin area. In order to find the sources of resistance among barley cultivars, 9 cultivars: Reyhan, Valfajr, Karoon, Aras, Jonob, Gorgan, Morex, Chevron and Roboust were tested in glasshouse. Inoculation was carried out by placing 40 barley seeds between two mycelium-covered plates. For evaluation of resistance and susceptibility of barley cultivars in field, two experiments were carried out. In the first experiment 13 barley cultivars Zarjo, Valfajr, Roboust, Reyhan, Kavir, Karoon, Chevron, Excell, Gorgan, Aras, Dasht, Jonob and CI 9539 were used. The isolate No. 19 of Pyrenophora graminea was grown on potato dextrose agar plates (90 mm) until the plates were covered with mycelia. The seeds to be infected were then placed on the plates and allowed to germinate at 4-5°C for 10 days. In the second experiment 18 barley cultivars: Gorgan, Karoon x Kavir, Goharjo, Aras, Eram, Makooye, C2, Reyhan, Jonob, Kavir, Dasht, Valfajr, Chevron, Excell, Roboust, C19539, Morex and Karoon were used. The method of seed inoculation was similar to the first experiment. The germinated infected seeds were grown in field conditions. Evaluation of disease symptoms was performed at different times after planting. Percentage of infected leaves and infected stems were determined. Results indicated that cultivars Jonob, Eram, Makooye and C2 had the least infection and were the most resistant cultivars. Cultivars Karoon, Zarjo, Valfajr, Reyhan, Kavir and Karoon x Kavir were susceptible. Cultivars Morex, Chevron, CI9539, Roboust, Excell and Goharjo had the intermediate reactions.
