採自亞洲熱帶地區及美洲地區的24種野生稻(Oryza perennis)及兩種水稻品種(Oryza saliva) 栽植於中央硏究院的農場。在植株長到孕穂期時，其葉之水溶萃取液分別進行生物以分析以檢測其植 物相剋潛能，另進行色層分析鑑定其相剋物質。結果顯示，植物相剋作用的潛能因野生稻品系而異。 此分化顯與該品系所產生的植物相剋物質有相關關係。植物毒性在萵苣上表現的程度顯然高於水稻者，此顯示萵苣對相剋物質較水稻者爲敏感。

To learn about genotypic variations in allelopathic potential, 24 strains of a wild rice, Oryza perennis Moench, collected from tropical Asian and American countries, and two rice cultivars (O. saliva L.), were planted at Nankang, and water extracts from their leaves and stems taken at the booting stage were used for bioassay with Chinese cabbage and rice seeds. The extracts were also used for chromatographic analysis to determine the contents of nine phenolic acids. The strains tested markedly differed in root-growth suppression rates in bioassay and contents of phenolic acids, but the two kinds of measurements were largely uncorrelated. The root-growth suppression -rate in Chinese cabbage was considered as representing the allelopathic potential better than that in rice. Stepwise regression analysis showed that a combination of several phenolic acids and their interactions could account for the root-growth supprssion rate in Chinese cabbage. The result of bioassay clearly indicates the main direction of differentiation in O. perennis strains.