Abstract
Heterosis, the superior performance of F1 hybrids, is commonly evaluated with yields and biomasses, which are directly related to economic value, but genetic factors affecting these values vary for each characteristic evaluated. Meanwhile, recent studies on epigenetic modification of the genome have indicated the importance of chromatin modification in phenotypic variation and its plasticity in F1 hybrids. To examine the involvement of epigenetic chromatin modification in hybrid growth, we induced changes of chromatin modification in inbreds and their inter-subspecific F1 hybrids of rice by inhibiting the activity of histone deacetylases (HDACs), and examined the effects on basic growth parameters using large-scale sequential image analysis combined with growth modeling. Changes in chromatin modification led to differential effects on inbreds and their hybrids in the intrinsic rate of single leaf growth. Our results indicate that inbreds depend on HDAC activity to maintain their intrinsic growth rate more than hybrids.
