Abstract
In 2005 , a crossed used by Line ×Tester among ten genotypes of Triticum durum are Atra-S , Crezo , Berch-1 , Azeghar-2 , LD-357-E , Sham-3 , Cimeto as male and Bakrajo-1 , ACSAD-65 and Om-Rabea-3 as female . In following year the seeds of the ten parents and their crossed were grown in the research farm of the college Dohok University using RCBD with three replication to study the genetic behavior of the yield and components . General and specific combining ability were estimated and heterosis . A significant differences between genotypes were shown for all the characters . some variation were found between the general combining ability effects , and the testers , however the parent (ACSAD-65) was superior to others . Crosses (Bakrajo-1×Crezo) , (Om-Rabea-3×Sham-3) exhibited significant specific combining ability effects in a desirable direction for all characters . Ratio of general to specific combining ability components were less than one for all characters . A broad sense heritability value was higher in all characters , while the heritability in a narrow sense was low . The average degree of dominance values was greater than one indicating a presence of over-dominance . Some hybrids were superior to others .
