Allelopathic potential of Malaysian invasive weed species on weedy rice (Oryza sativa f. spontanea Roshev).
In laboratory bioassay, we studied the effects of methanolic extracts of 30-Malaysian invasive weed species (9 families) on the seeds survival rate and seedlings growth of Weedy rice (Oryza sativa f. spontanea Roshev). Five concentrations [6.25, 12.5, 25, 50, 100 (g L-1)] of methanolic extracts were used and control was distilled water. The Weedy rice seeds survival rate and seedlings growth (radicle and hypocotyl length) of 7-day-old seedlings were reduced by the increasing concentrations of extracts than control. Probit analysis and the concentrations required for 50% inhibition (EC50) showed that radicle growth was more suppressed than seeds survival rate and hypocotyl growth. Among the tested weed species, Parthenium hysterophorus L., Cleome rutidosperma DC. and Borrreria alata (Aubl.) DC. proved strongly allelopathic and thus, could be used to develop eco-friendly herbicides.