Evaluation of Allelopathic Potential of Pluchea indica on Brassica chinensis and Zea mays

Weeds have become one of the leading causes of crop production losses, including the cost of weed management, weed crop competition, and weed intervention with crop management practices. Moreover, herbicide use in agricultural systems is currently being debated due to the potential adverse effects on the environment and human health. The utilization of the allelopathic phenomenon is widely considered an alternative weed management strategy. However, allelopathic study of Pluchea indica plant was limited. P. indica is a flowering plant under family Asteraceae, locally known as Beluntas. Thus, this study was conducted to determine the allelopathic effects of the aqueous leaf extract of P. indica on the seedling growth of tested plant species and to investigate the effect of P. indica leaf debris on the growth of tested plant species. In this study, the allelopathic potential of P. indica leaves were investigated through petri dish bioassay and soil bioassay method. The two tested plant species were chosen for the bioassay: monocotyledonous; maize (Zea mays) and dicotyledonous; mustard (Brassica chinensis). These tested plant species were chosen for the experiment due to their known quick seedling growth behaviours and commonly used in allelopathic studies. The result showed that as the concentration of aqueous leaf extract increased, the inhibition percentage of the radicle length of B. chinensis and Z. mays were increased. However, stimulatory effect was observed on the radicle length of B. chinensis and Z. mays when 1.3%and 2.5% w/w  P. indica leaf debris were applied. Thus, aqueous leaf extract and leaf debris of P. indica have potential allelopathic effects on the growth of B. chinensis and Z. mays. Further studies need to be conducted on other bioassay species especially weed species, to elucidate the allelopathic potential of P. indica in weed control.