Abstract:
The allelopathic effects of P polystachyon stem plus leaves extracts and debris on
growth of several weeds and crops species were examined under greenhouse
conditions. Weedy plants of Eleusine indica and Heydotis verticillata and edible crops
of Amaranthus caudatus and Zea mays were bioassay species studied. Pennisetum
polystachyon extracts stimulated the height of A. caudatus at lower concentration (50
and 100g/L) but no significant effect was observed for A. caudatus at the highest
concentration (150g/L). All three concentration of P polystachyon extracts induced E.
indica to grow. Besides, there was no allelopathic effect observed for Z. mays and H.
verticillata at the low concentration (50g/L). Zea mays was tolerant to I OOg/L but was
inhibited at the highest concentration (150g/L). Heydotis verticillata were inhibited at
100 and 150g/L. It is found that the allelopathic effect of extracts on some bioassay
species is concentration dependent.
