Abstract:Effects of polarity and concentration of NAA on the ability of producing hairy roots incucumber cotyledon explants infected by Agrobacterium rhizogenes R1000 and R1601 were studied.The results showed that hairy roots appeared only at the hasal part of cucumber cotyledon explantsinfected with A. rhizogenes R1000 and R1601. If 0.1mg L-1 and 5.0 mg L-1 NAA were added to MSmedium, the rooting ability of the basal part of cotyledon infected with A. rhizogenes R1000 andR1601 was enhanced. However, in treatment only with 5.0 m L-1 NAA in precureandcocultivation on MS medium, the hairy roots could be incited in the apical part of cucumbercotyledon infected with A. rhizognes R1000 and R1601. Opine analysis evidenced the intergraionand expression of TR-DNA.