In normal cotton plants and in a variety with short fruiting branches, labelled assimilate was translocated to fruiting bodies on upper and lower sympodia when the sympodial leaf on the first node of the fourth sympodium was treated with I4C sucrose. Main stem leaves similarly treated, exported the assimilate to fruiting bodies only on the lower sympodia in the long-branch variety whereas in the short-branch variety, the assimilate also reached the upper sympodia. This higher efficiency of the main stem leaf in short-branch cotton may be related to a reduction in the translocation path because of the particular spatial arrangement of its leaves and fruits.