Allelopathic effect of neolmarckia cadamda (roxb.), bauhinia variegata l. and grewia optiva (drumm ex bur.) on zea maize l., triticum aestivum l. and sesamum indicum l

The presence of allelochemicals in many tree species show antagonistic effect on germination and growth of understorey agriculture crops and affect the yield of these crops. It is well known fact that every tree species shows antagonistic or synergic effect on understorey crops. Neolmarckia cadamba, Bauhinia variegata and Grewia optiva are fast growing species and being introduced under agroforestry for their multi-purpose use. An experiment to observe the allelopathic effect of N. cadamba, B. variegata and G. optiva was conducted in laboratory conditions by using their 25% (T1), 50% (T2), 75% (T3) and 100% (T4) leaf extract along with a control on Triticum aestivum, Zea maize and Sesamum indicum. The results showed that application of T1, T2 and T3 leaf extract of N. cadamba, showed the maximum germination in seeds of S. indicum while in T4, no germination was observed in S. indicum except Z. maize where it was maximum in comparison of T. aestivum. In all 4 treatments (T1, T2, T3 and T4) of B. variegata, the germination of seeds of S. indicum was maximum. Similarly, in T1 and T2 leaf extract of G. optiva, the germination in seeds of S. indicum was maximum. In T3 and T4 leaf extract, the germination in seeds of Z. maize was maximum. Overall, the germination of maize, wheat and sesame was also found varied from 61.67% (T. aestivum) to 100% (S. indicum). The T4 (100%) leaf extract of N. cadamba had inhibited the germination completely in S. indicum under laboratory conditions. Under field conditions, there was no major difference observed in number growth of tillers of Z. maize, T. aestivum and S. indicum germinated at tree line and away tree line showing no allelopathic effect on germination.