the genetic control of in vitro direct regeneration was tested on seedlings of ten open-pollinated progenies from the base population of atherton origin of eucalyptus grandis at university of s？o paulo (brazil). seeds were germinated in vitro, after twenty days, distal hypocotyls segments from 196 seedlings per progeny were inoculated in culture media at generalized complete randomized block design, with two experimental units per block and seven repetitions, using the interaction blocks by progenies as an estimate of the experimental error. at week 14 from the inoculation bud induction was evaluated. regeneration among progenies were significantly different (p<0.0001). regeneration varied from 11 to 60%. the narrow-sense heritability between means of experimental units for in vitro regeneration was height. (h2m=0.94), indicating a strong genetic control of the trait within the population and also a high maternal effect. high variability within the study sample was found.