Effect of Salinity Stress on Chickpea (Cicer ariethinum L.) Genotypes in Seedling Stage under Hydroponic Conditions

Salinity is a global challenge to crop production. Chickpea grow under a wide range of climatic conditions and is highly sensitive to salt stress. Salt stress causes osmotic, ionic and secondary stresses, impairing various metabolic processes in plants and eventually decreases plant yield. Using salinity tolerant chickpea cultivars could be effective in increasing production and productivity of saline fields due to their ability in biological nitrogen fixation. The aim of the present study was to evaluate the effect of salinity on physiological responses of 17 chickpea genotypes in seedling stage.

To determine the most tolerant genotype to salinity stress, a split plot experiment was conducted based on randomized complete block design (RCBD) with three replications in Ferdowsi University of Mashhad, Mashhad, Iran. 17 Kabuli chickpea genotypes as sub plot, two salinity levels (12 and 16 dS.m-1 NaCl) and a control (0.5 dS.m-1) as main plot were evaluated. Salinity stress was applied two weeks after sowing. Four weeks after salinity stress was imposed, traits including electrolyte leakage, photosynthetic pigments, total phenol, soluble carbohydrates, proline content, osmotic potential, survival percentage, sodium and potassium content of shoots and salinity tolerance index were measured.

In all genotypes, with increasing salinity stress level, survival percentage decreased and electrolyte leakage percentage increased. In the 16dS.m-1 NaCl treatment, MCC72, MCC108 and MCC112 genotypes had the highest survival percentage of 86.5, 82.6 and 100%, respectively. In salinity level of 16dS.m-1, MCC108 genotype showed the lowest percentage of electrolyte leakage (82%) and MCC12, MCC58 and MCC27 genotypes showed the lowest increase in the percentage of electrolyte leakage compared to the control. The chickpea genotypes showed different responses by increased salinity in terms of photosynthetic pigment content. In MCC92, MCC108, MCC112 and MCC296 genotypes, content of chlorophyll a increased as salinity level increased to 16dS.m-1. Soluble carbohydrates and proline content in all genotypes increased and osmotic potential became more negative as salinity levels increased from 0.5 (control) to 16 dS.m-1.

In general, there was a wide variety among chickpea genotypes based on physiological traits. The analysis of clusters of genotypes was divided into five groups. Cluster analysis and mean comparison showed that the survival percentage in MCC108 and MCC112 genotypes were higher than total mean, so supplementary field studies on these two genotypes are recommended.