Allelopathic Effect of Various Tree Species on Germination and Root Growth of Crop Plants

This experiment was undertaken to elucidate the allelopathic effect of four commonly grown farm trees namely, Casuarina equisetifolia, Pongamia pinnata, Mangifera indica and Tectona grandis on germination per cent and root length of Paddy, Sorghum and Ragi crops. The study was carried out at College of Forestry, Sirsi, University of Agricultural Sciences, Dharwad during the year 2004. Mature fresh leaves of above mentioned tree were crushed and soaked for 8h, 16h and 24h and used to investigate their effect on the test crops. These leachates shown both stimulatory as well as inhibitory effect on the paddy seed germination. Average germination percentage was suppressed more by C. equisetifolia and less by T. grandis leachates. Average germination percentage of sorghum was repressed more by T. grandis leachates. Leaf leachet of P. pinnata and M. indica showed the positive response to the root length of Sorghum. With regard to germination percentage of Ragi, leachates of M. indica and T. grandis are at par with the control whereas, positive response recorded for C. equisetifolia leachet over control. The results revealed that the leaf leachates of tree species are most of the time inhibits the germination and radical growth.