Furthermore, allelopathic rice PI312777 released allelochemical 5,7,40-trihydroxy-30,50-dimethoxyflavone into paddy soil at their early growth stages (maximal level of 47.5 7.2 mg g1 soil at seedling stage) and then declined dramatically at elongation stage. While non-allelopathic Liaojing-9 released significantly low concentrations of the flavone during
the whole growth stages (Table 1).