**5. Conclusions**

This study has shown the strategic interest of referring to climate and crop modeling for the prediction of the impacts of future climate change on the rainfed durum wheat yield in the High eastern plain of Algeria. For the baseline period 1981–2010, the climate model ICHEC\_KNMI used in this study has proved its reliability in simulating temperatures and net solar radiation with good precision. However, precipitations are simulated with less certainty, given the high variability of precipitation in Algeria, which made the simulation very complicated. The AquaCrop crop model was used to assess the impacts of future climate change on grain yields, length of the growth cycle, and the water productivity of the durum wheat cultivar, Mexicali, in 2035–2064, under RCP 4.5 and RCP 8.5. This study showed that the effect of the increase in CO2 concentrationsin the atmosphere made it possible to avoid the drop yields of the rainfed Mexicali cultivar. This decline in grain yield could be induced by the negative effects: of the drop in precipitation and net solar radiation and by the increased air temperatures projected over the growing season of this cultivar in 2035–2064, under RCP 4.5 or RCP 8.5. Moreover, this study proved that the increase in temperature expected in 2035–2064 under the above scenarios, causes a shortening of the duration of the growth cycle of the Mexicali cultivar. However, an increase in yields and water productivity of this cultivar are projected by this future horizon, thanks to the fertilizing effect of the enrichment of the atmosphere with CO2. This study has made it possible to plan a strategy for adapting rainfed durum wheat to rising temperatures by applying early sowing in October, which avoids the loss of yield during the wheat growth cycle very sensitive stage, of grain filling in spring. However, further research is needed, using climate projections from an ensemble of climate models instead of a single model, to reduce the observed uncertainties in the precipitation simulation. It is necessary to evaluate, under RCPs scenarios, with other crop models, the effect of supplemental irrigation and fertilization on the adaptation of this Mexicali cultivar and other durum wheat cultivars to future climate change. Thus, the association of climate and crop modeling proves to be a relevant tool that meets the needs of farmers in terms of choice of farming practices and cultivars, in order to reduce the negative impacts of climate change on crops yields, as it enables decision-makers in the agricultural sector to plan sustainable and effective policies to help farmers to face the projected climate change and avoid crop yield losses, thereby maintaining food security in Algeria.

**Author Contributions:** T.K. collected, corrected, analyzed, simulated crop data with AquaCrop, interpreted the crop and climate data and wrote the initial draft of the paper. D.S. provided some data and supervised and corrected the paper, she also, reanalyzed and reinterpreted some data and contributed in the improvement of the manuscript contain and quality. A.M. read and contributed in improvement the English editing of the paper. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to restriction imposed by the National office of meteorology in Algeria.

**Conflicts of Interest:** The authors declare no conflict of interest.
