Effect of Biological and Chemical Fertilizers on Growth Traits and Yield Components of Mung Bean (Vigna radiata L.) under Copper Toxicity Stress

In order to investigate the effect of different levels of copper and application of biological and chemical fertilizers on morphological traits, yield components and grain yield of mung-bean (Vigna radiata L.), a factorial experiment was conducted based on randomized complete block design with three replications. The first factor was soil contamination with copper including 0, 50, 100 and 200 mg/kg of soil and the second factor was different fertilizer treatments including  chemical fertilizer, Sinorhizobium meliloti bacterium, Piriformospora indica mycorrhizal-like fungus, Sinorhizobium + Piriformospora and no fertilizer treatment (control). The results showed that plant height, leaf number and leaf area per plant were decreased under high Cu concentration and the highest values were observed in application of P. indica. The highest shoot and root dry weight of mung beanwere obtained at 50 mg/kg Cu. Application of P. indica, S. meliloti and chemical fertilizer increased the root dry weight more than other treatments. The highest grain yield per plant (1.045 g) was obtained by application of chemical fertilizer in 0 mg/kg of Cu. Fertilizer treatments had no significant effect on pod number, but the application of P. indica + R. meliloti increased the seed number per pod. Significant decreases in studied traits of mung-bean in higher concentrations of Cu indicate that mung-bean is susceptible to copper toxicity stress.  The mean comparison of the fertilizer treatments showed that application of chemical fertilizer and P. indica in lower concentrations of Cu resulted in increase of mung-bean tolerance to Cu toxicity. Also at high concentrations, using S. meliloti resulted in higher tolerance to Cu toxicity compared with other treatments.