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Abstract

Abstract:Previous studies have shown that the Caryota urens seed pericarp possesses botanicals capable of inhibiting seed germination. Extracts made from C. urens pericarp were tested at different concentrations to find out its inhibitory activity. Three rice varieties (Bg 305, Bg 358, Bg 368) and the rice weeds (Echinochloa crus-galli, Ischaemum rugosum and Ipomoea aquatica) were tested. Percentage germination was measured for 7 days at 2 day intervals. The methanol extract of dried seed pericarp significantly reduced the seed germination, indicating that the concentration of the inhibitory substance/s in C. urens pericarp is higher in methanol extracts than the water extracts. Dried seed pericarp showed the highest inhibitory effect on the seed germination. The germination of all rice cultivars and weed species tested were completely inhibited by 100 and 200 mg.ml -1 concentrations, suggesting that the C. urens seed pericarp has a seed germination inhibitory effect on all weeds tested. In general, the germination inhibitory effects were maximal at high concentrations than at lower concentrations. Potential for using C. urens pericarp for weed control is highlighted.