show Abstracthide AbstractHeterosis refers to the phenomenon that progeny of intra- or inter- species cross exhibit greater biomass, speed of development, and fertility than both parents. To understand the mechanisms of heterosis, we analyzed transcriptome, sRNAome and methylome profiles from 2 weeks old seedlings of two Arabidopsis thaliana accessions and their reciprocal hybrids. Subsequently, we compared these data of F1 hybrid and their parents and discussed whether transcriptional and epigenetic variation between F1 hybrid and their parents were associated with heterosis.