evaluation of commercial sugar beet cultivars for resistance to cercospora leaf spot under field condition

resistance of 16 sugar beet cultivars to cercospora leaf spot was evaluated in ghaemshahr region. the experiment was conducted in a complete block design with six replications and disease severity of cultivars was measured two times. as a winter crop the root yield of cultivars and their disease severity compared under natural cercospora infection in dezfoul area in a complete block design with four replications. reaction of sugar beet cultivars to cercospora leaf spot was similar in ghaemshahr and dezfoul. the most resistant and susceptible cultivars to cercospora leaf spot were palma and 191, respectively. the cultivars palma, canaria, 4k21 and hi0152 produced highest sugar yield in dezfoul area and showed highest resistance to the disease in two regions. the lowest amount of sugar was produced by genotypes 191 and br1. it seems that for introducing appropriate cultivars to the region, yield and resistance of the disease under stress condition should be considered.