Effects of leaf extracts of common home garden trees on food crops

In Lab. bioassays and pot culture, the effects of aqueous leaf extract of 5 home garden trees [Artocarpus heterophyllus L., Mangifera indica L., Areca catechu L., Citrus indica Tanaka and Tamarindus indica L.] were studied on the germination, shoot length and root length of 5 food crops [Capsicum annum L. (Chilli), Glycine max (L.) Merr. (Soybean), Zea mays L. (Maize), Oryza sativa L. (Rice), and Abelmoschus esculentus (L.) Moench (Lady’s finger)]. Air-dried fresh leaves of selected trees were crushed and soaked in water, diluted to prepare extracts concentrations for bioassay and pot culture. In bioassays, the inhibitory effects of leaf extracts on germination were upto 85.2% over control in chilli. Shoot length was most adversely affected in lady’s finger, while the root elongation was suppressed in paddy.

In pot culture, maximum inhibition in seed germination was exerted by T.indica (37%) followed by C. indica (19.5%), M. indica (13.1%), A. heterophyllus and A. catechu (12.4% each) of all the test crops, germination and seedling vigour was severely decreased in lady’s finger. Most of the food crops, except paddy were inhibited by Tamarindus leaf extract and hence, are incompatible. Soybean was also sensitive to Artocarpus extracts, while germination and growth of lady’s finger was inhibited by all tree species except Artocarpus. Paddy was resistant to allelopathic effects of all tree species.