Abstract
Germination of mungbean (Vigna radiata) seeds and its seedling fresh weight, hypocotyl and epicotyl lengths were notably reduced by increasing levels of taro (Colocasia esculenta) residue extract. The effect on corn (Zea mays) seed germination and seedling development was not clear. The negative correlation obtained between residue level and percentage germination was significant in mungbean and okra (Hibiscus esculentus) (r = -0.885 and r = -0.959, respectively) but not in corn and eggplant (Solanum melongena) (r = -0.565 and r = -0.312, respectively). Increasing levels of taro residue incorporated in a sand growing medium stimulated production of more but shorter roots in taro plants. Among residue extracts of sweet potato, cassava and taro, only that of taro exhibited a detrimental effect on mungbean seed germination and hypocotyl elongation. Generally, taro residues exhibited an allelopathic effect and its activity was species-specific and level-dependent.
