مقاومت ژنوتيپ هاي اميدبخش گندم اقليم سرد در برابر بيماري زنگ زرد

Resistance Reaction of Promising Wheat Genotypes of Cold Zone to Yellow Rust

Yellow rust caused by Puccinia striiformis f. sp. tritici, is a globally important fungal disease of wheat (especially in Central and Western Asia) that cause significant annual yield losses. Its varies from one area to another, depending on climate and predominant cultivars. In order to control disease, use and production of resistant cultivars is the best method. For this purpose, the reaction evaluation of 20 promising wheat genotypes of cold zone with a susceptible check was conducted on yellow rust in Ardabil. Each genotype was planted in two 1 m rows 30 cm apart under mist irrigation and artificial inoculation. The experiment was conducted in 2001 -2003 cropping years, based on completely randomized block design with three replications. To increase disease development, a susceptible cultivar (Bolani) was sowed among lines (10 entry intervals) and also as borders of Nursery. Besides, the artificial inoculation of the nursery was carried out using a mixture of spores and talcum powder at sun set and Gs36 stage by means of a duster. Thtf disease severity and infection type were recorded respectively based on the modified Cobbʹs scale and Roelfs et al. method. Then, coefficients of infection (CI) were calculated by combination of disease severity and infection type. The results showed that there are significant differences among lines. The lines of C-80-3, C-80-4, C-80-5, C-80-11, C-80-12, C-80-16 and C-80-20 were highly resistant, where as, C-80-2, C-80-13, C-80-18 and C-80-21 (check) lines were susceptible. The rest of lines were moderately resistant or moderately susceptible that located between two mentioned above groups.