Effect of sodium nitroprusside on photosynthetic pigments and grain yield of rapeseed under different irrigation regimes

In order to investigate the interaction between sodium nitroprusside and drought stress on photosynthetic pigments and their relationship with yield and yield components of rapeseed, an experiment was conducted during two cropping years (2015-16 and 2016-17) at Hamedan Agricultural and Natural Resources Research Center. The experiment was carried out as a factorial in randomized complete block design with three replications. Experimental factors were irrigation levels including full irrigation (control), irrigation termination from beginning silique stage and irrigation termination from grain filling stage, and four treatments of foliar application of sodium nitroprusside with concentrations of 0, 100, 200 and 300 μM. The results showed that irrigation termination significantly reduced the amounts of studied traits. Sodium nitroprusside foliar application increased the amounts of photosynthetic pigments, yield and grain yield components under drought stress and non-stress conditions. The highest and the lowest grain yield were obtained in the combination treatments of plant foliar application with 300 mM sodium nitroprusside and full irrigation (5129 kg/ha) and non-foliar application and irrigation interruption at the beginning silique stage (3396 kg/ha), respectively. The experiment indicated that sodium nitroprusside application can have positive effects on photosynthetic pigments, yield components and grain yield of rapeseed under drought stress and non-stress conditions, and therefore its application can greatly mitigate the adverse effects of drought stress in water deficit conditions.