M.A. Thesis:

The effect time and amount of di ammonium phosphate foliar application on yield and yield components of Cotton

formation stage of cotton can be obtained the best seed cotton yield and lint yield. In order to determination og the nest time and concentration of Diammonium phosphate ((NH4)2HPO4) on yield and yield component of Cotton in saline condition, An experiment was conducted as factorial arrangement based on randomized complete block design in Sabzevar in 2015-2016. Factors were: Diammonium phosphate concentration (0, 0.1, 0.2 and 0.3%) and time of foliar application (at early flowering, at peak boll formation and at early flowering+peak boll formation ). Varamin cultivar used in this study. Foliar application was done as 600 lit.ha-1. Plant height, monopodial and sympodial branch number, number of open and unopen bolls, boll weight, seed cotton per boll, lint percent, seed cotton yield, lint yield and biological yield were studied. Varamin cultivar used in this study. Increasing of Diammonium phosphate concentration to 0.3% increased plant height (20.1%), monopodial branch number (31.13%), sympodial branch number (37.27%), boll number (32.08%), boll weight (41.17%), seed cotton per boll (58.48%), seed cotton yield (39.29%) and biological yield (35.71%) compared than control. Foliar application at early flowering+peak boll formation had the highest plant height, sympodial branch number, seed cotton yield and biological yield, while the highest number of opened bolls was in spraying Diammonium phosphate at flowering stage and the highest monopodial branch number, seed cotton per boll and boll weight was recorded at peak boll formation. . Overall results showed that spraying with Diammonium phosphate at a concentration of 0.3% at early flowering+peak boll

Keywords: Diammonium phosphate , Foliar application, Time of spraying, Salinity