**3. Conclusions**

Increasing greenhouse gases emission have led to global warming and climate change worldwide. The global climate change consequences, *that is,* elevated CO2 concentration, water stress, and extreme temperatures, are serious problems affecting the photosynthetic efficiency and adaptation of plants and adversely affecting agricultural yields. Studies suggest that most plants will be more stressed and less productive in the future in response to climate change. Climate change reduces photosynthetic capacity directly by damaging photosynthetic structures and processes. The changes and modifications of the photosynthetic machinery under different stressful conditions can be evaluated by the chlorophyll fluorescence analysis. Analyses of chlorophyll fluorescence seem to be a promising tool for breeding crops with improved tolerance under stressful conditions. Therefore, the application of chlorophyll fluorescence can be useful to identify which part of the photosynthetic apparatus is affected by the stress and it might help identify good-performing genes by chlorophyll fluorescence to be used in breeding programs.
