Abstract MON810 is a genetically-modified (GM) maize (Zea mays) event commonly employed in insect-resistant GM maize hybrids. GM events obtained by biolistic transformation methods, such as MON810, are generated by insertion of a recombinant gene expression cassette in a random locus of the plant genome, and this process may cause emergent properties besides the intended modification. Here, we compared morphophysiological parameters of MON810 GM maize hybrid AG-5011YG and its non-GM near-isogenic hybrid (NIH) AG-5011, using in vitro cultures as an interactive model. NIH callogenesis frequency, callus friability, and de novo morphogenesis were compared using two explant types and different 2,4-dichlorophenoxyacetic acid (2,4-D) levels. 2,4-D modulated the morphophysiological responses of both NIHs, but when using root segments as explants, the GM showed significantly different trends for callus induction and friability, with lower responses at higher 2,4-D concentrations, indicating an emergent property related to altered cell response to 2,4-D.