Response of cotton plant to the indole-3-butyric acid application under n fertilization rates.

Two field experiments were carried out during 2011 and 2012 seasons at Sids Agricultural Research Station. ARC, using cotton cultivar Giza 80 to study the effect nitrogen fertilizer rates (45, 60 and 75kg/fed) and foliar spraying of indole -3- butyric acid (IBA) at four rates (0, 10, 20 and 30 ppm) on growth characters, yield and yield components as well as fiber properties and chemical contents. Increasing nitrogen fertilizer rates from 45 to 60 or 75 kg/fed significantly increased for plant height, number of internodes/plant, internode length, number of fruiting branches/plant, boll setting percentage, number of open bolls/plant, boll weight, earliness percentage, seed cotton yield (Kentar/fed) and chemical contents of cotton plant (leaves and seeds). On the other hand, position of first fruiting node and fiber properties showed insignificant responded to nitrogen fertilization. Result revealed that the IBA at 20 ppm was significantly enhanced plant height, No. of internodes/plant, internode length, boll setting %, No. of open bolls/plant, boll weight, seed cotton yield, chlorophyll (A), carotenoids, protein and oil percentage. On other hand, position of first fruiting node, fiber properties, chlorophyll (B) and total chlorophyll. However, No. of fruiting branches and earliness % response only in one season. Generally, the interaction between N and IBA had highly significantly affected all studied characters, except position of first fruiting node, yield and yield components and chemical contents as well as (leaves and seeds) of cotton plant were not affected by the interaction between treatments with refer to apply 75kg N/F and spraying 20ppm IBA.