In order to evaluate the genetic variability of wheat resistance to sunnpest damages, forty wheat cultivars composed of durum and bread wheat were tested in the College of Agriculture, Razi University in Kermanshah, in a randomized complete block design (RCBD), with three replications. The analysis of variance showed that there are significant differences among the means of leaf damages by sunnpest in different cultivars. Based on leaf damages, Duncan’s multiple ranges test (DMRT) revealed that Chanab and Gafgaz are the most susceptible cultivars, whereas, Atila-5 (Shahid Chamran) and durum 20-1-54 are the most resistant ones. There was also a significant difference between the mean number of eggs oviposited by the overwintered female mother sunnpest, on the leaves of different wheat cultivars. The highest number of eggs was oviposited on the Chanab and Gafgaz cultivars (the least resistant ones) whereas the lowest number of eggs oviposited on the leaves of durum 10-B and Yavarus cultivars (the most resistant ones). Duncan’s test showed that dorum 25-1-49 was the most succeptible while the Atila-12 (Shahid shirudi) was the most resistant cultivar. Duncan’s test was also used for evaluating the percentage of wheat seed damage by sunnpest. This test showed the Sabalan and genotype durum 8B were susceptible, whereas, Atila-5 (Shahid Chamran) and Ghods cultivars had the lowest percentage of seed damage (the most resistant ones). The T-test was used for making a comparison between feeding of sunnpest’s nymphs on the wheat kernels of different wheat cultivars. The cultivars, which were attacked by sunn’s nymph, had significantly reduced thousand seed weight, as compared to control. With regard to protein quality, T-test showed significant lower protein quality as compared to control. A comparison between attack of sunnpest to the durum and bread wheat, the T-test showed that the injuries to the leaves and kernels of the former were less serious than to those of the latter. The use of correlation test, did not show a significant correlation between the morphological characters of wheat seeds and the percentage of seed damage. The total resistance coefficients showed that the cultivars Omid, Rashid, Atila-12, Atila-5 and Gods are relatively resistant while the cultivars Chanab and Gafgaz are susceptible. Cluster analysis of forty genotypes with the four resistance characters showed that the cultivars Omid and Atila-12 were the most resistant cultivars while Chanab and Gafgaz were the most susceptible ones.
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