Abstract:The effects of parentals drought hardening on physiological characteristics and DNA methylation in maize were studied. Maize B73 and H99 selfbred offspring (G1 generation) were used as materials which parents (G0 generation) were trained by drought. The relative water content (RWC), the contents of malondialdehyde(MDA), soluble sugar, proline and the activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of G1 and G0 generations were measured by using 20% PEG6000 to simulate drought condition, and the methylation status of genome in G0 and G1 generations was detected by amplified fragment length polymorphism (MSAP) technique, and the variation of physiological indexes and genomic DNA methylation modification in two generations of maize were analyzed. The results showed that: (1) under the same drought treatment, the RWC, soluble sugar and proline contents, the SOD and POD activities of B73 and H99 in G1 generation were higher than those in G0 generation, the MDA content in G1 generation was lower than that in G0 generation, the RWC reduction and MDA increase in G1 generation were lower than those in G0 generation, and the increase of soluble sugar and proline contents, SOD and POD activities in G1 generation were higher than those in G0 generation. (2) The DNA methylation levels and patterns in two generations of B73 and H99 were changed which caused by drought stress. Under the same drought stress, the changes of DNA methylation in G1 generation were greater than that in G0 generation. (3) The variations of DNA methylation in B73 and H99 were different. The methylation level of CG and CHG in B73 2 generations and the methylation level of CG in H99 2 generations were increased, and the methylation level of CHG were decreased. The variations of CG hypo and CHG hypo were dominant in B73 and CHG hypo and CG hyper were dominant in H99. The abilities of antioxidation, osmotic adjustment and the changes of DNA methylation in G1 generation of B73 and H99 were higher than that in G0 generation, and the drought resistance in G1 generation was higher than that in G0 generation. These results showed that there was transgenerational drought stress imprint in maize.