Indole-3-acetic acid concentration in roots and production of roots in rtce due to application of zinc and granular insecticides

IAA concentration in rice roots and the root production in rice as influenced by zinc and soil applied granular insecticides was studied at Tamil Nadu Agricultural University, Coimbatore. The treatments involved a factorial combination of two levels of Zn (0 and 25 kg ZnSo₄/ha) and three levels of insecticides (no insecticide, carbofuran @ 0.75 kg ai/ha and phorate @ 1 kg ai/ha). Zinc-insecticide interaction was synergestic in rice to enhance the IAA concentration in fresh roots. Application of zinc sulphate @ 25 kg/ha with Carbofuran (@ 0.75 kg ai/ha resulted in highest concentration of IAA in roots (496 microgram/kg fresh root). Interaction between phorate (@ 1.0 kg ai/ha) and Zn was also positive resulting in the production of 393 microgram of IAA per kg of fresh root. Application of zinc, carbofuran or phorate could enhace the root production in rice at all stages of plant growth.