Use of Salsola soda as a companion plant to improve greenhouse pepper (Capsicum annuum) performance under saline conditions

A greenhouse experiment was carried out to evaluate the effect of Salsola soda used as a desalinating companion plant on growth, yield, mineral composition, and fruit quality of pepper (Capsicum annuum) grown under moderate (electrical conductivity (EC) = 4.0 dS m(-1)) and high salt concentration (EC = 7.8 dS ml(-1)). The presence of S. soda decreased the EC of the medium by 45% and increased the total yield, marketable yield, and total biomass of pepper by 26%, 32%, and 22% respectively, in comparison with those grown without S. soda. The increase in marketable yield under moderate salt stress with S. soda was the result of a higher fruit mean weight and not the number of fruit. S. soda did not prevent suppression of growth and yield on pepper under severe salt conditions. Increasing the nutrient solution salinity improved fruit quality by increasing dry matter (DM) and total soluble solid (TSS) content. Under moderate saline conditions, the concentrations of sodium (Na) and chloride (Cl-) in pepper leaves were lower when S. soda was used as a companion plant, whereas no difference was recorded on Na and Cl concentrations of leaves at 7.8 dS m(-1). A higher concentration of nitrogen (N), potassium (K), and calcium (Ca) was observed in pepper leaves in the presence of the companion plant at 4.0 dS m(-1). The results demonstrate that using S. soda as a companion plant under moderate saline concentrations would be an attractive strategy in limiting yield reduction.