the stable and transient expression of the gusa-intron reporter gene in internodal explants of "papa criolla" cultivar criolla colombia co-cultivated with agrobacterium tumefaciens is reported. in order to determine the susceptibility of this cultivar to the a. tumefaciens-mediated transformation, internodal explants of solanum phureja were infected by a. tumefaciens containing the vector pcambia2301. this vector contains the kanamycin resistance gene ntpii and the reporter gene gusa-intron. the selection of potential transgenic explants was performed on kanamycin-containing media. the stable and transient transformation efficiency was calculated on the basis of the gus (？-glucuronidase) activity, detected by the histochemical x-gluc essay. transient and stable expression of the gusa-intron gene is observed in explants cells rather than in whole tissues. nonetheless, these results demonstrated that "papa criolla" (solanum phureja juz. et. buk) cultivar criolla colombia is susceptible to the agrobacterium tumefaciens infection.