Means and variances for six generations PI, P₂, F_l, BC_I, BC₂ and F2 in the
intraspecific cross (G. 86 x G. 85) were used to estimate types of gene action,
heterosis, degree of dominance, heritability in broad and narrow senses and expected
genetic advance of selection. Highly significant useful heterosis were found for days to
first flower, seed cotton yield, lint index, lint % and boll weight. heterosis were
significantly negative and disivable for days to first flower and days to first opening
boll, while it was positive for lint % and boll weight. Estimates of inbreeding
depression were significant for all studied traits except days to first opening boll . The additive gene effects were significant for days to first opening boll, seed cotton
yield and 2.5% span length. Dominance gene effects were detected for most studied
traits. Moderate to low heritability in broad and narrow senses were observed for
most studied traits. Low expected genetic advance values were detected for days to
first flower, days to first opening boll and 2.5% span length.