Genetic Stability in Some Bread Wheat Cultivars

Eight bread wheat cultivars (Adnania, Abu-graib 3, Ipa 99, Cham 4, Tammoze 2, Rabia, Fateh and Mexipak) were planted during 2010- 2011 and 2011-2012 growing season at two different locations (Erbil and Duhok) and two sowing dates (15 November and 15 December) bringing the total of eight environments using Randomized Complete Block Design with three replications in order to evaluate the stability of these cultivars. Five stability parameters [Variance across environments (EV), Homeostasis (H %), Genotypic resultant (GR), regression coefficient (Bi), variance of deviations from regression (S²di)] were used to identify the stability of these cultivars at eight various environments in yield and its components. The results showed different response among cultivars for environments. Some cultivars were stable for one character and unstable for another and no cultivar had superior performance in all Environments, suggesting that the genetic factors consists of geneticenvironment interactions differ between characters. The stability parameters showed a wide range of variation between cultivars for all characters. The cultivars Cham 4, Tammoze 2 and Mexipak had the best values according to all parameters of stability; hence, it has a wide adaptability over a range of environments of rainfall conditions in Iraq.