The objective of this study was to analyze the inheritance of the resistance to cotton ramulosis. For thispurpose, two groups of lines with contrasting performance for the evaluated trait were crossed. The disease-susceptibleparents were Delta Opal, CNPA 999 and CNPA 2161, and those with resistance BRS Facual, CNPA 2043 and CNPA 2984,resulting in nine crosses, always of one resistant and one susceptible parent, totalizing 42 treatments. The experiment was setup in a randomized complete block design with three replications. It was verified that the genetic control of ramulosisresistance is predominantly oligogenic, and the number of genes involved depends on the parents that participate in eachcross, due to the possibility of differential loci fixation. Evidence of partial dominance in the sense of increasing diseaseresistance was found, but there were also indications that dominance is not unidirectional
