Abstract
The superior performance of hybrids (heterosis) is generally evaluated with traits such as yield and biomass that are directly related to agricultural importance; however, the dependence of these characters on multiple genetic factors and their interaction with the environment have obscured the common molecular mechanisms underlying heterosis. Here, by using a newly developed system for time-lapse monitoring of the growth of rice seedlings, we have characterized parameters in the early growth of F1 hybrids between japonica and indica varieties of Oryza sativa L, especially with respect to the effect of chromatin modification. Inhibition of histone deacetylases induced apparently similar growth retardation in both inbreds and hybrids independent of their relative growth rates. However, detailed characterization of growth parameters by regression showed that the decrease in the growth rate could be divided into components that showed distinctive responses to TSA treatment between inbreds and hybrids.
