Effect of drought stress chemical and biofertilizer and salicylic acid on grain yield and yield components of Coriander (Coriandrum sativum L.)

Abstract
Background and objectives: Drought is one of the major stresses that adversely affect crop productivity and quality in many arid and semi-arid parts of the world, and the aim of this research the effects of drought stress, fertilizer and salicylic acid on some of morphological and agronomic characteristics of coriandrum.
Materials and methods: A field study was conducted in Kermanshah province during year of 2014. The experiment was laid out as split-factorial arrangement based on a randomized complete block design with three replications. Experimental factors were combination of 3 levels of drought stress 60, 90 and 120 mm evaporation from class A pan and fertilizer in 4 levels control, urea 100 kg.ha-1, biofertilizer of Nitrokara and 50% urea + Nitrokara and the concentration of salicylic acid 0 and 1 mM. The traits were included number of umbel per plant, number of umbelet per umbel, number of grain per plant, 1000 grain weight, biological yield, grain yield and harvest index.
Results: The results showed that number of umbel per plant, number of umbelet per umbel, number of grain per umbelet, number of grain per plant, 1000 grain weight, biological yield, grain yield and harvest index were decreased under drought stress. In contrast of salicylic acid and combination of urea with Nitrokara significantly increased in the all evaluated traits. Interactions effects fertilizer × irrigation trait of number of grain per umbelet showed that the maximum and minimum mean in traits of drought stress 60 mm evaporation from class A pan and 50% urea + Nitrokara with mean of 14.25 and trait of drought stress 120 mm evaporation from class A pan and control with mean of 5.33 to be obtained. Also mean comparison of interaction effects of irrigation × salicylic acid showed maximum and minimum mean of number of grain per umbelet in trait of drought stress 60 mm evaporation from class A and application of salicylic acid with mean of 13.91 and drought stress 120 mm evaporation from class A and non-application of salicylic acid with mean of 6.1 and also mean comparison of interaction effects of fertilizer × salicylic acid showed maximum and minimum mean of number of grain per umbelet in traits application of salicylic acid with combination of 50% urea and Nitrokara with mean 11.11 and control with mean 8 respectively. Interaction effects of irrigation × fertilizer × salicylic acid was significant in the all evaluated traits (with the exception of number of grain per umbelet) and application of salicylic acid with combination of urea and Nitrokara in all levels of stress particularly in normal irrigation condition (60 mm evaporation from class A pan) and drought stress 120 mm evaporation from class A with control had highest and least amount respectively.
Conclusion: According to the results, application of salicylic acid (1 mM) and biofertilizer Nitrokara involvement in remove of negative effects of stress and application of salicylic acid and biofertilizer Nitrokara could be increased grain yield and yield components of coriander as valuable medicinal plant under drought stress.