| To study combining ability and type of gene action controlling of yield inheritance and some related traits in maize , a field experiment was conducted on the firm of the Dept.of Field Crop Sci./Coll.of Agric./Univ of Baghdad. A diallel cross with one direction was done among five inbred lines of maize introduced from Italy ( CO1159,CO1255 ,CO1010 ,CO1506 and CO1398). The inbreds were sowed at Spring season 2009 to produce ten crosses. In the next season, Autumn 2009, a field trail included parents and crosses by using randomized complete block design was conducted. Statistical analyses revealed significant differences in general combining ability and specific combining ability in all traits studied.The inbred CO1159 was the best general combiner in chlorophyll index ,leaf area and ears per plant , while the inbred line CO1398 was the best combiner in number of grains per ear and grain weight. Also the CO1010 was superior in grain yield . The cross,CO1398 x CO1010 was superior in hetrobeltosis% in many traits value were : grain yield ,leaf area, number of grain per ear and chlorophyll index 48.04% , 27.7% , 23.7% and 7.49% respectively. The heritability in broad sense was high but in narrow sense was low ,as a result of increasing dominance variance values. Therefore, the average degree of dominance was more than one in all traits studied .It was concluded that these inbreds have a high genetic diversity especially, Those gave a best general combiner for producing composites varieties or that gave a high specific combining ability effects ,so they can be exploited in producing hybrids. |