فهرست نشریات علمی دسترسی آزاد ایران

Objective: This research aimed to employ crop simulation modeling to identify key traits for improving water-limited yield (Yw) of rainfed wheat (Triticum aestivum L.) across Iran's diverse agro-climatic zones under current and projected future climates.Methods: Using the Global Yield Gap Atlas (GYGA) upscaling protocol and the SSM-iCrop model, simulations were conducted for 32 reference weather stations (RWSs) representing 72% of Iran's national rainfed wheat area. Historical (2000–2015) and future (2041–2060; RCP4.5, +1.9 °C, 500 ppm CO₂) climate scenarios were analyzed to evaluate the impact of modifying physiological traits.Results: Under the current climate, the national mean simulated Yw was 2.02 t ha⁻¹, ranging from 1.04 to 4.41 t ha⁻¹. Future climate increased mean Yw to 2.87 t ha⁻¹ (range: 1.54–5.33 t ha⁻¹), due to CO₂ fertilization and accelerated development, alleviating terminal drought. Trait analysis revealed that increasing the grain-filling duration by 20% was the most effective and consistent strategy, boosting national mean yield by 0.30 t ha⁻¹ (current climate) and 0.47 t ha⁻¹ (future climate) in high-rainfall Caspian Sea zones. Conversely, shortening the vegetative phase by 20% increased yields by up to 0.1 t ha⁻¹ in terminal-drought regions of the Zagros Mountains but reduced yields in eastern and northeastern Iran, with negative impacts intensifying under future climate. Decreasing phyllochron provided modest yield gains (>5% in 7 RWSs) under the current climate, but its benefits diminished under future warming. Increasing radiation use efficiency had a limited impact under both climate conditions. Spatial analysis showed the primary key trait was extending grain-filling for 13 RWSs (current) and 16 RWSs (future), while shortening the vegetative phase was key for 11 and 12 RWSs, respectively. Critically, in 9 RWSs across western/northwestern Iran, the optimal trait shifted with climate change, underscoring strong G×E interactions.Conclusion: Breeding for enhanced grain-filling duration offers a robust, climate-resilient strategy for most parts of Iran. In contrast, manipulating vegetative growth duration requires precise, region-specific targeting due to its variable and sometimes negative effects. These results provide a spatially explicit blueprint for trait-based breeding to enhance the productivity and climate resilience of Iran's rainfed wheat systems.