Abstract
Grain size is the main factor determining rice yield. Recently, several genes controlling grain size have been cloned leading to have achieved the new aspect about the mechanism determining grain size. Among them, loss of function of 4 genes enlarged grain size and these results suggested the existence of a kind of limiting system that determines grain size. Functional analysis of 5 genes elucidated that the spikelet hull size might mainly explain the natural variation in grain size. In this article, we reviewed the new aspect about regulation of rice grain size.
