Effect of salicylic acid and spermine on yield and yield components of castor bean (Ricinus communis L.) under drought stress

Castor been plant is a forgotten crop which its cultivation has experienced a lot of ups and downs in the world, and given the key role of the castor oil in different industries, an experiment was carried out to study the effect of salicylic acid and spermine on yield and yield components of castor bean under drought stress as split plot based on randomized complete block design with three replications in 2012. The irrigation regime was considered as the main plot, based on the fraction of the class A pan evaporation (0, 0.2 and 1.2% CEA), and spraying of salicylic acid (0, 250 and 500 µM) and spermine (0, 10 µM and 1 mM) were arranged as sub plots. Drought stress significantly decreased the number of capsule per plant, number of seed per plant, grain yield, biological yield, 100- seed weight and harvest index. Salicylic acid and spermine treatments significantly affected the yield and yield components of castor bean under drought conditions. The greatest yield was obtained with 250 µM salicylic acid. Salicylic acid and spermine alleviated the drought stress impact, while the effect of salicylic acid showed a greater significant effect on crop yield than that of spermine treatments.