**3.3 Dehydration tolerance**

Dehydration tolerance of a genotype means that a significantly lower level of changes in it than those in another genotype when both of them are subjected to the same level of dehydration. Various measurements of dehydration tolerance are as follows. i) maintenance of membrane integrity by low levels of solute leakage. ii) seedling growth parameters like seedling survival or recovery, seedling growth, seed germination under osmotic stress created by Polyethylene glycol (PEG), stem reserve mobilization, presence of awns in cereals, high levels of proline accumulation. Plant drought response mechanisms and main related traits (**Figure 1**).

**Figure 1.**

*Plant drought response mechanisms and main related traits.*
