Evaluation of tolerance of 20 wheat cultivars to Russian wheat aphid Diuraphis noxza (Mordvilko) at seedling stage under greenhouse conditions.

The Russian wheat aphid (R.W.A) is an aggressive pest of wheat, barley and other small grains in different parts of the world and during, the recent years in Iran. This aphid causes high damage, so that much insecticides have been used against it. At present time utilization of resistant varieties is one of the most important methods to control it. Therefore in order to evaluate the tolerance of 20 wheat cultivars, seeds were planted in 18 cm diameter plastic pots and put in cages. One week after infestation the seedling foliage were cut and put in separate plastic bags, also roots were washed and put in other plastic bags. Number of aphids and plant heights and weights were analyzed based on ANOVA and treatment means were compared. The results indicated that the cultivars of yavaras, Arvand mutant, Bezostia and Alamut had a high tolerance at seedling stage.