Graphics analysis, components of genetic variation and heritability, for the characters: plant height, number of vegetative branches, number of fruiting branches, number of bolls per plant, boll weight and seed cotton yield, were computed from a half diallel set of seven cotton varieties (Halab90, Sp8886, Delta pine5409, Lachata, Dunn1047, Coker310 and Deer22). The variance due to dominance were generally higher than the additive for all studied characters. Graphics analysis suggested the presence of epistatic gene effects (non-allelic interaction) in high proportion for number of bolls per plant and boll weight, as well as additive gene effect with partial dominance for plant height, number of vegetative branches, number of bolls per plant, and seed cotton yield. Moderate narrow sense heritability was observed in case of plant height whereas low for the remaining characters.