ABSTRACT To investigate the response of wheat to drought stress under different plantation systems, two field experiments were carried out in 2021/22 and 2022/23 in Arsanjan. The main plot was three different plantation systems (flat planting, 60-cm raised beds, and 120-cm raised beds) and the subplots were irrigation levels at 100% (control), 80% (medium stress), and 60% (severe stress) of crop evapotranspiration. The results showed that the raised-bed planting increased grain yield by 22.1 and 25.9% compared to flat cultivation in the first and second years, respectively. This increase in the biological yield was about 17%, the number of ears was 7%, and the number of seeds per ear was 21%. Drought stress caused a significant decrease in grain yield (46.4%), number of ears (20.5%), seed number (30.3%), biological yield (45.9%), chlorophyll a (31.8%), chlorophyll b (28.1%) and relative water content (5.3%) and increased, proline content (24.3%), and ion leakage (147.3%). The decrease in yield due to drought stress was moderated in the raised-bed system and therefore cultivation on the raised-bed is suggested as a suitable planting pattern to improve the yield and water efficiency in wheat under conditions similar to the experimental area, especially under water shortage conditions.
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