Estimation of genetic parameters and effective wheat under field condition factors in resistance to Septoria Leaf Blotch of

Abstract: Septoria leaf blotch disease is caused by fungal agent Seproria tritic (Rob) Desm. In other to estimate the genetic mean components and effective factors controlling of resistance against septoria leaf blotch in adult plant stage, six basis generations (P1, P2, F1, F2, BC1, BC2) of cross between a promising line introduced from International Maize and Wheat Improvement Center (CIMMYT) along with two cultivars (Tajan and Moghan3) were planted in an experimental design of complete randomized blocks in the field of agricultural research center of Gorgan, Golestan. The studied traits include disease severity and disease severity area under the disease progress curve (sAUDPC). For both studied traits in crosses of promising line×Tajan and promising line×Moghan3, additive and dominance effects had a significant role in STB resistance. In promising line×Tajan and promising line×Moghan3 crosses, the selected model for disease severity is quite similar to the model for sAUDPC; it may be due to the high correlation between these traits. The additive×additive [i] and dominance×dominance [l] nonallelic interactions had significant effect in studied traits. There was only a significant heterosis for sAUDPC in cross of promising line×Tajan. The minimum number of genes or effective factors controlling in resistance to STB disease was varied between one to two in crosses.