3. Test of Combining ability (1)Combining Ability (GCA, sCa)(see p. 89) GCA--Mean value of a line over the Grand mean of all the crosses GCA= Mean of Line a- grand mean of all crosses SCA---Performance of a specific cross(i.e. A X B) The Deviation of the following equation: SCA=(Value ofA x B)-grand mean-GCAA-GCAB3. Test of Combining Ability (1)Combining Ability (GCA, SCA) (see p. 89) GCA --- Mean value of a line over the Grand mean of all the crosses.: GCA = Mean of Line A – Grand mean of all crosses SCA --- Performance of a specific cross(i.e. A x B) The Deviation of the following equation: SCA= (Value of A x B) – Grand mean – GCAA - GCAB