The objective of this research was to quantify boll set percentage and value of fruiting sites for four cotton cultivars. The study was in 1994 at La Laguna Experiment Station, Mexico. The experimental design was a randomized complete block with four replications. The Mexican varieties Cian Precoz, Cian 95, Launa 89 were compared with the commercial cultivar Deltapine 80. Data was taken on 100 plants on each cultivar to mapped where the harvestable bolls were produced.

Results showed that in modern cultivars Cian Precoz and Cian 95, 78 and 73 % of all harvestable bolls were produced at position one sites on sympodia branches. On the other hand, cultivars Deltapine 80 and Laguna 89 produced 69 and 63 % of all their harvestable bolls at position one. These results indicate that the crop should be managed to provide optimum opportunity for these sites to set and mature bolls.