White rot is an important disease of sunflowers. Sunflower genotypic responses to S. sclerotiorum have to be evaluated with precision. White rot disease could be assessed by components of partial resistance and this would help to evaluate accurately genotypic responses. Here we wish to show which of variables or components of white rot are most suitable for describing sun flower performance during disease cycle. Twelve sunflower genotypes have been grown in an experiment and then inoculated. Disease incidence, relative incubation period, disease severity (observed at two moments), and the growth lesion rate were scored. All variables showed variability among the genotypes. The disease incidence and relative incubation period were confirmed as com ponents of partial resistance. The results also indicated that the growth lesion rate during the intermediate and last phases of the disease seemed most appropriate to be used simultaneously with disease incidence and relative incubation period. If these three components were selected simultaneously, developed cultivars would have a more complex resistance and they would be less prone to the disease.