SCREENING OF LEAF AND BARK EXTRACTS AND GUM EXUDATE OF SELECTED SPECIES IN THE FAMILY MELIACEACE FOR EFFECTS ON GERMINATION OF STRIGA HERMONTHICA SEEDS.

ABSTRACT

This study investigated the potential effects of leaf extract, bark extract and gum exudate of six selected species from the family Meliaceae, on the germination of Striga hermonthica during and after preconditioning. The selected species of the family Meliaceae includes; Carapa procera, Cedrela odorata , Azadirachta indica, Khaya ivorensis, Khaya grandifoliola and Khaya senegalensis. For the first experiment, S. hermonthica seeds were preconditioned with sterilized water and after 14 days a germination stimulants (GR24, 5ppm) was added alongside with the extracts and exudates at different concentrations, six concentrations were used as treatments, 0%(control), 5%, 10%, 20%, 50% and 100%. While in the second experiment, extracts and exudates of the selected plant species were added with the seeds during preconditioning. Results from the first experiment (after preconditioning) revealed that S. hermonthica germination was not significant in the presence of the plants extracts used, while S. hermonthica seeds germination was significantly higher in the presence of gum exudates from the selected species. Results obtained from the second experiment (during preconditioning) revealed that S. hermonthica germination was not significant in the presence of both plant extracts and exudates from the selected species. This could be evidence that S. hermonthica seed when dormant in the presence of these selected species before it is stimulated by susceptible host plant, germination would probably be hindered.