Six divergent cotton genotypes were crossed in un-constructed to be 15 F1 crosses then, F2 were obtained. All genotypes were evaluated in Randomized Complete Block Design with three replicates. Genetic parameters of natural performance of genes were estimated by Hayman method (1954) for characters of Boll weight (B.W.), Seed cotton yield (S.C.Y.), Lint yield (L.Y.), Seed index (S.I.), Lint percentage (L. %), Lint index (L.I.) and oil%. The result showed that additive and dominance variance H1 and H2 values were significant for all traits, and the additive values were less from dominant values, that refers to the importance of dominance variance in its inheritance. Also the H2 values were less than H1 which recorded that the allelic frequencies were not equal. The overall dominance effects of heterozygous loci (h2) were significant for all traits in both generations, indicating that the dominance was due to heterozygosity and was unidirectional with appreciable heterotic effect. The proportion of dominant to recessive gene in parents KD/KR were more than unity for most studied traits. The average degree of dominance (H1/D)0.5 exceeded unity for all studied traits in both generations, indicating that presence of over dominance for these traits. High values for heritability in broad sense were obtained for all traits, revealing that most phenotypic variability in each trait was due to genetic causes. High heritability values in broad sense along with medium or low ones in narrow sense were exhibited in both generations, indicating that most genetic variances were due to non-additive genetic effects. The regression line passed through the origin in boll weight in generations, seed index, lint percentage and oil% in F1, revealed a presence of complete dominance. Meanwhile, it intersects the Wr axis above the origin in lint yield and oil% in F2, reflecting partial dominance. The P4, p2, P2, P5, P5, P2 and P5 in F1, P4, P2, P1, P5, P6, P3 and P6 in F2 for for B.W., S.C.Y., L.Y., S.I., L. %, L.I and oil%, respectively seemed to have the highest number of dominant genes.