Abstract
The re-accumulation of starch in the stem (culm and leaf sheath) of rice cultivars at harvest was examined from the viewpoint of the sink-source relationship as one of the characteristics of rice whole crop silage. Although stem starch content at harvest was high in some japonica cultivars, it was low in semi-dwarf indica cultivars. Some traits related to sink or source organ, especially in japonica cultivars, correlated with stem starch content at harvest. Spikelet number and the rate of increase in panicle dry weight per spikelet during the early-middle stage of ripening showed a significant negative and positive correlation with stem starch content at harvest respectively. Stem dry weight and leaf dry weight per spikelet at the middle stage of ripening also showed a significant positive correlation with stem starch content at harvest. These results suggested that the difference among japonica rice cultivars in their stem starch content at harvest could be determined from the size of their sink (grain and stem) and source (leaf) organs and the growth rate of the grain during the ripening period.
