Abstract: In this study, the three-compartment rhizobox method was used to collect soil samples from three different root zones of a maize plant, i.e. growth room (S I), rhizosphere (S II) and non-rhizosphere (S III) and the traditional plate count method and DGGE were applied to investigate changes in population and diversity of soil bacteria at D40, D50 and D60 after sowing of transgenic Bt maize and its parental maize. Results show that cultivation of transgenic Bt maize significantly reduced the population of soil cultivable bacteria in Zone S I at D50 and D60, but increased the population in Zone S II at D40 and D50, and showed no significant impact in the other zone. DGGE fingerprints indicated no significant difference between soil samples taken at different dates in DGGE bands, diversity index and homogeneous degree index of the bacteria (P>0.05).

Key words: transgenic Bt (Bacillus thuringiensis) maize, soil bacteria, DGGE, rhizobox