The widespread use of plant mapping in recent years has resulted in numerous applications and a keen awareness of plant architecture in cotton. Plant architecture has been a consideration in the development of cultivars adapted to production under narrow rows. Entries from half diallel mating system involving four Delta-type cultivars and two stripper-type cultivars were planted in the field and arranged in a randomized complete block design with four replications. Plots consisted of one row 40 ft in length with 38 in row spacing and 4 in plant production practices were implemented throughout the season. After defoliation, several plant mapping traits were measured from six plants within each plot. Analysis of variance of the six parents indicated significant differences among parents for each trait measured except for total length and average length of all sympodial branches. Data from F₁ entries were subjected to Griffing's method 4, model 1 diallel analysis. Significant differences among entries were indicated for plant height, node of first sympodial branch, height of first sympodial branch, number of monopodia, and number of sympodia. No differences were observed for the combined length of all sympodial branches or average sympodial branch length. General combing ability (GCA) was significant for each of these traits except for number of sympodial branches and total length of all sympodial branches. Specific combining ability was not significant for any of the traits measured. Significant GCA implies that genetic variability is additive. Additive genetic variability allows for prediction of values for plant mapping traits in progeny from crosses of parental material. This information should be useful in selecting parents in a breeding program designed to change plant architecture to fit a particular production practice such as use of narrow row spacing.