Response of Soilless Grown Sweet Pepper Cultivars to Salinity

Agricultural productivity and sustainability are the most challenges facing many arid and semiarid regions as these regions are characterized by severe shortage of good quality water for irrigation and saline water is very common. The trend in recent years has been towards conversion of conventional agriculture to soilless agriculture (mainly closed system) which is considered to be a more efficient use of water system. The aim of this research was to examine the response of three sweet pepper cultivars (Capsicum annum L., cvs. Flaviano, Sonar, Alzado) to different levels of salinity under soilless recirculating conditions. Plants were grown in concrete troughs filled with zeolite in a closed soilless system using nutrient solutions with NaCl corresponding to electrical conductivity levels [1.8 (control), 4 and 8 dS m(-1)]. The sweet pepper proved to be sensitive to the increasing salinity of nutrient solution as the total and marketable fruit yield, fruit number and single fruit weight decreased in all tested cultivars with increasing salinity level. However, genotypic variation for fruit yield and yield components have been noticed. The cultivar Flaviano produced higher fruit yield than the other two cultivars regardless of salinity level. In all cultivars, leaves had higher Na+ and Cl- concentrations than fruits, which increased with increasing salinity; while K+ in leaves was higher than fruits and decreased by salinity. Leaves and fruits of the cultivar Flaviano accumulated higher K+ and lower Na+ and Cl- than the other two cultivars. This suggests that Flaviano was the most tolerant cultivar to salinity among tested cultivars as it showed less reduction in fruit yield and its components due to salinity.