Utilization of heterosis has significantly increased rice yields. However, its mechanism remains unclear. In this study, comparative transcriptional profiles of three super-hybrid rice combinations, LY2163
, at the flowering and filling stages, were created using rice whole-genome oligonucleotide microarray. The LY2163
hybrids yielded 1193, 1630 and 1046 differentially expressed genes (DGs), accounting for 3.2%, 4.4% and 2.8% of the total number of genes (36,926), respectively, after using the z
< 0.01). Functional category analysis showed that the DGs in each hybrid combination were mainly classified into the carbohydrate metabolism and energy metabolism categories. Further analysis of the metabolic pathways showed that DGs were significantly enriched in the carbon fixation pathway (p
< 0.01) for all three combinations. Over 80% of the DGs were located in rice quantitative trait loci (QTLs) of the Gramene database, of which more than 90% were located in the yield related QTLs in all three combinations, which suggested that there was a correlation between DGs and rice heterosis. Pathway Studio analysis showed the presence of DGs in the circadian regulatory network of all three hybrid combinations, which suggested that the circadian clock had a role in rice heterosis. Our results provide information that can help to elucidate the molecular mechanism underlying rice heterosis.