-

To study the genetics of resistance to sunn pest in bread wheat, two resistant and two susceptible lines were crossed to each other as follow: 14 × Ghafghaz, 75× Sardary, 75× Ghafghaz, 14× Sardary. Their F1, F2, BC1 and BC2 progenies after being produced were planted along with their parents using a randomized complete block design with three replications. In early seed development stage, five sunn pests were introduced in each cage having five wheat plants. After twenty days, percent damaged seeds along with their genetic characteristics were assessed through generation mean analysis method. Joint scaling test indicated that the resistance to sunn pest is controlled by additive, dominance, and epistasis, especially dominance × dominance, and additive × dominance effects and, to a lesser extent by additive × additive effects. Minimum and maximum broad sense heritability were 0.22 and 0.80 while minimum and maximum narrow sense heritability were 0.03 and 0.79 respectively. Number of genes controlling this trait were estimated from 1 to 4 for these lines.