Abstract :
In order to study the effects of terminalheat stress and nitrogen on morphophysiological characteristics, ANUE (Agronomy of Nitrogen Use Efficiency) and yield of canola (Brassica napus L.) an experiment was conducted in research farm of Ramin Agricultural Sciences and Natural Resources University, Iran, during 2009-2010. The experiment was arranged in split plot based on complete randomized block design with 4 replications. Main plot included three fertilizer treatments consisted of 90, 180, and 270 kg.ha-1 nitrogen and control (to computation of ANUE). Sub plots were considered two sowing date (11 Nov.) optimum condition and (26 Jan.) terminal heat stress condition. Results showed that terminal heat stress and nitrogen had significantly effect on allmeasured parameters while effect of nitrogen on ANUE was not significant. Between two levels of 180 and 270 kg.ha-1 nitrogen hadno significantly effect on plant height, leaf number, sub branch number, LAI and ANUE. In addition, interactions effects between terminal heat stress and nitrogen were significant on parameters. In both of optimum and terminal heat stress condition, enhanced in nitrogen led to significantly increased yield. Nitrogen had no significant effect on ANUE. Decrease in nitrogen levels resulted to decrease of final grain yield. Also terminal heat stress decreased the grain yield about 59 percent. Our result suggested that increased nitrogen could have a positive effect on terminal heat stress tolerance of canola.
