Study of resistance components at seedling stage to leaf rust (Puccinia triticina Eriksson) in some commercial cultivars

Leaf rust caused by Puccinia triticina Eriksson is a major foliar disease of wheat, resulting in yield loss all over the world. In order to study the resistance components to leaf rust, a collection of 31 wheat cultivars was screened under controlled conditions at seedling stage inoculated with an isolate (race CHHLS) which had been collected from Lorestan province in complete randomized block design with 3 replications. Latent period was determined by the number of days after inoculation to the appearance of first pustule on the leaf 8 days after inoculation started and continued until 12 days after inoculation. Infection types on primary leaves were rated 12 days after inoculation using the Roelfs method in a scale of 0-4. The cultivar Orom, showed the lowest infection type, the longest latent period however, the cultivar Bolani had the shortest latent period and the highest infection type. Analysis of variance showed that there was a significant difference for infection type, but not for latent period among cultivars. There was a strong negative correlation (r= - 0.6463) between infection type and latent period. Cluster analysis based on ward’s method, categorized the cultivars into three groups as Resistant (Khazar1, Golestan, BKRB, Bam, Neyshabour, BKRZ, Hirmand and Oroum), Moderately Resistant (Sistan, Kavir, Parsi, Navid, Moghan1, Moghan2, Mahdavi, Aflak, Mihan, Alamout, Bahar, Darab2, Shiraz, Chanab, Alborz and Falat) and Susceptible (Zare, moghan3, Atrak, Zarin, Arg, Arvand and Bolani).