Allelopathic Effects of Extracts from Maize Roots and Rice Husks’ Residues on the Germination and Growth of Bidens pilosa L.

Screen house experiment was conducted to examine the allelopathic effects of the extracts from residues of maize root and rice husk on the germination and growth of Bidens pilosa L. The extracts brought about considerable inhibitions in all the growth parameters of the extract-treated seeds examined. The degree of retardation of both extract treated seeds increased with increase in the concentration of the extracts which showed that the inhibition was concentration dependent. The results obtained showed that the degree of retardation appeared to be more pronounced in B. pilosa seeds treated with extract from maize roots in growth parameters such as number of leaves at harvest and leaf area, relative growth rates, dry roots and shoot weights were inhibited. Similarly the degree of retardation was more pronounced in rice husk extract-treated seeds in growth parameters such as germination percentage and speed of germination. Statistical analysis (P < 0.05) revealed that there were significant differences in germination %, dry shoot weights of B. pilosa seeds treated with 40 g and 50 g maize roots extract concentrations when compared to the control experiment while other concentrations showed no significant difference to control experiment. Also, speed of germination, number of leaves at harvest and leaf area of B. pilosa seeds treated with extracts from residues of maize roots showed significant differences when compared with the values obtained from the control experiments. However, there were no significant differences in the all the growth parameters with rice husk treated seeds compared to control experiments. Similarly, no significant difference was observed in the relative growth rate of B. pilosa seeds treated with maize root extracts compared to control experiments.