The breeding between Gossypium hirsutum L. and Gossypium barbadense L. purpose to increase yield and enhance fiber quality. The cross populations between four hirsutum varieties, Darmi, Helius, LT 4 and LT 64 and barbadense variety, Avesto, were used as material. Interspecific F1 and F2 populations were evaluated in terms of heterosis, useful heterosis and F2 depression for yield, quality parameters and physiological characteristics such as stomatal density and parenchyma thickness in cross section of leaf. All observed characters resulted negative heterotic effects except fiber length and strength. Inbreeding depression for seed cotton yield was highly negative in all hybrid combinations. The differences among genotypes for stomatal density and parenchyma thickness were found to be significant. The significant correlations showed that an increase in stomatal density resulted in an increasing of fiber length and strength, whereas in a decreasing of ginning out turn and fiber fineness. It should be concluded that stomatal density can be used as selection criteria in early generations of interspecific cotton breeding.