Increasing salinity levels pose significant challenges to coastal vegetable cultivation, particularly impacting salt-sensitive crops like cucumber, leading to reduced growth, development, yield, and quality. This study assessed the responses of six commercial cucumber cultivars to different salinity levels. Cucumber plants were grown in a hoop house hydroponically using various dilutions of brackish water in a Nutrient Film Technique (NFT) system at EC levels 3, 6, and 12 dS/m, along with adequate controls (0 dS/m). Increasing salinity levels caused a significant decline in plant growth parameters (shoot length, biomass, leaf number). Overall a 59% reduction in shoot length and 52% decrease in dry biomass was observed at 12 dS/m compared to control. The cultivar, Stripped Armenian had significantly greater shoot length (163 cm) and dry biomass (59 g), compared to the others (Diva, Katrina, Lemon, H-19 Little Leaf, and Suyolong) by 52-207% and 126-409%, respectively. Additionally, Stripped Armenians dry weight exceeded the control by 120%, 115%, and 25% in 3, 6, and 12 dS/m treatments, respectively. Gaseous exchange parameters measured with Licor 6850 (photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration) declined significantly with increasing salinity at vegetative and reproductive stages. The photosynthetic rate and stomatal conductance showed reductions of 15-17% and 13-50%, at salinity levels of 3 dS/m, 6 dS/m, and 12 dS/m, compared to the control treatment respectively. Similar reductions were also observed at the reproductive stage. Stripped Armenian consistently exhibited higher photosynthetic rate (4-27%), stomatal conductance (7-75%), and transpiration rate (6-56%) compared to other cultivars at vegetative and reproductive stages. In conclusion, Stripped Armenian demonstrated substantial tolerance to 12 dS/m salinity compared to other cultivars and may prove useful in saline environments, however further research is needed.
