Improving Cucumber Salt Tolerance by Grafting on Cucurbit Rootstock

Soil and water salinity is one of the stresses that have limited cucumber production in Iran. The use of cucurbit rootstocks is a valid strategy in increasing cucumber salt tolerance. In order to investigate the effect of the grafting on Shintoza, Cobalt, and Root power rootstocks in salinity condition (40, 60 and 80 mM NaCl) on yield, growth, fruit quality, electrolyte leakage, leaf area, specific leaf area (SLA), SPAD index, leaf relative water content (LRWC), mineral composition, and proline of cucumber plants (cv. Khasib), an factorial experiment was carried out based on completely randomized design (CRD) with three replications. Salinity improved fruit quality in both grafted and ungrafted plants by increasing fruit dry matter and total soluble solids content. Moreover, at the three salt treatments the percentage of yield and biomass reduction was significantly lower in the grafted plants in comparison to ungrafted plants. Grafted cucumber plants exposed to NaCl were capable of maintaining higher fruit yield, plant growth, leaf area, leaf relative water content (LRWC), higher chlorophyll content (SPAD index), a better nutritional status in the root and leaf tissues and higher proline concentration and less electrolytic leakage in comparison with ungrafted ones. These results suggest that rootstocks have a higher capacity for Na exclusion and retention, which resulted in reduced Na transport to the shoot and increased the salt tolerance of cucumber.