Data from the 1,131 birds of synthetic population (A) and 1,587 birds of selected population (D) for three generations were analyzed to determine the different components; additive variance, maternal genetic variance and covariance between additive-maternal genetic effects of economic traits. Coefficients of variations of mean performances in synthetic line were decreased and those of selected line were nearly constant year by year. It was found that maternal genetic variances were important in all traits except egg weights before 43 weeks of age in both lines, showing greater values in synthetic line than in selected line. Correlations with additive-maternal genetic variances, when present, were highly negative in all traits which seemed to influence to derive difference between heritabilities from sire and dam variance components through sib analysis in the absence of dominant effect. Adjusted heritabilities included additive variance, maternal genetic variance and covariance between additive-maternal genetic effects were large in body weights at different age and small in egg numbers and initial egg weights of both lines.