Preliminary Evaluation of Tithonia diversifolia (Helms.) A. Gray for Allelopathic Effects on Some Selected Crops under Laboratory and Screenhouse Conditions (pp 111-113).

http://www.globalsciencebooks.info/JournalsSup/images/WebJournals/AJPSB_4%28SI1%29Web.pdf 

O. Samuel Olabode, G. Olulakin Adesina, S. Adelani Babarinde, E. Olabimpe Abioye (Nigeria)

ABSTRACT

Research Note: Tithonia diversifolia (Helms.) A Gray leaf extract was evaluated for its allelopathic activity against maize (Zeamays), soybean (Glycine max) and okra (Abelmoschus esculentus) seeds at 38 ± 2°C and 69-75% relative humidity in the laboratory. Screenhouse studies were also carried out on the same crops. The concentrations tested in the laboratory experiment were 100, 50, 20 and 0% of the extract. Maize seed germination was not significantly (P< 0.05) affected by T.diversifolia extract across the concentrations tested. At 100% concentration,T. diversifolia extract significantly lowered soybean germination. There were significant differences in the germination of okra seeds but without a trend. The highest germination percentage (88%) occurred at 100% concentration while the least (80%) occurred at 50% concentration and the control. The screenhouse treatments were: (a) sterilized soil + water, (b) natural soil + extract, (c) natural soil + water and (d) soil under Tithonia canopy + water. The result from the sceenhouse experiment showed that except for the number of leaves of okra, soil under Tithonia canopy + ordinary water did not show any conspicuous negative effect on the tested parameters when compared with the control.