The effect of salt stress on yield and accumulation of some minerals in two salt-tolerant and susceptible onion cultivars

Salt stress is a major agro-environmental constraint on crop productivity. In this study, the effect of different levels of salinity stress (0,25,50,75, and 100mM NaCl) on the accumulation of some ions in two salt-tolerant and susceptible onion cultivars (Esfahan and Behbahan cultivars, respectively) was investigated in 2017. The research was done by a factorial experiment based on a completely randomized design with three replications. The results showed that salinity increased Na and Cl contents and also decreased K content in the leaf and root in both cultivars. However, Na and Cl contents in the leaf and root of the susceptible cultivar were significantly higher than those in the tolerant cultivar, while the K value was less. In both cultivars, the Cl content in the leaf and root decreased with increasing salinity. However, the amount of Ca in the tolerant cultivar was higher than that in the leaves and roots of the susceptible cultivar. Salinity only significantly reduced Mg in the leaves. The amount of phosphate decreased at low salinity levels and increased as salinity increased. Yield injury index was in significantly negative correlation with K,Ca, K/Na, and Ca/Na ratios and in significantly positive correlation with Na and Cl in the leaves and roots. The results indicated the salt-tolerant cultivar plays a role in reducing the Na and Cl uptake, as well as increasing the absorption and transfer of K and Ca to the leaves. Therefore, it could cause low yield injury under the salinity conditions compared with the susceptible cultivar.