*2.4. Electrolyte Leakage Analysis*

Electrolyte leakage (i.e., membrane permeability) was measured at 29 DAS collecting three leaf disks (10 mm diameter each) from fully expanded leaves on 3 plants per *Genotype* × *NaCl concentration* combination and immersed in 50 mL of distilled water. EC was measured immediately (1 min -) (EC1) and after 60 min of shaking (EC60). The samples were then autoclaved (121 ◦C) for 25 min, and total conductivity (ECT) of bathing solution was measured after cooling. Electrolyte leakage was calculated and expressed as a percentage (%) according to Blum and Ebercon [17] using the following Equation:

Electrolyte leakage (%) = (EC60 − EC1)/ECT.

### *2.5. Statistical Analysis*

A completely randomized design was adopted for the experiment. The experiment was conducted on a total of 40 plants per *Genotype* × *NaCl concentration* combination and each analysis was carried out on at least 3 plants per *Genotype* × *NaCl concentration* randomly selected. Data were analyzed by ANOVA using SPSS 25 software package (www.ibm.com/software/analytics/spss) and means were compared using Duncan post hoc test (*p* ≤ 0.05). The cluster heatmap was generated using the ClustVis online software [18] using Euclidean distance as the similarity measure and hierarchical clustering with complete linkage on the genotype percent variation, log (x+1) transformed, between 150 and 0 mM of NaCl on all the analyzed parameters. The principal component analysis (PCA) was conducted using the Primer 6 software package (PRIMER-e, Albany, New Zealand) on the percentage variation of all the morphological and physiological analyzed parameters to highlight differences between genotypes to the increase of NaCl concentration in the nutrient solution. Five components were extracted by the PCA analysis. The PCA output includes treatment component scores as well as variable loadings.
