Tarbiat Modares University Journal of Agricultural Science and Technology 1680-7073 28 3 2026 05 01 Root Architectural Diversity in Wheat Cultivars and Its Role in Response to Terminal Water Stress 715 730 24099 10.48311/jast.2026.24099 EN Afshin Zamani Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. Yahya Emam Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. Aref Nowrouzi Department of Plant Production and Genetics, School of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran. Journal Article 2025 09 16 Root architecture plays a key role in optimizing water uptake and sustaining yield under drought stress. The aim of this study was to investigate the role of vertical root distribution in determining the performance of three irrigated wheat cultivars under Terminal Water Stress (TWS). A field experiment was conducted during the 2021–2022 growing season at Shiraz University, evaluating three bread wheat cultivars: Pishgam, Torabi, and Sirvan. The low-cost "pasta strainer" method was adapted and employed to assess wheat mature root architecture in this context. To assess vertical root distribution, roots protruding through the side perforations of strainers were counted at three defined depth intervals: Shallow (2–8 cm; SRN), middle (8–10 cm; MRN), and deep (10–13 cm; DRN). The results revealed significant differences in root architecture among cultivars. Compared to Sirvan and Torabi, Pishgam exhibited a more uniform root distribution across SRN, MRN, and particularly DRN. A significant interaction between irrigation and cultivar was observed for root weight, root volume, shoot biomass, and Grain Yield (GY). Pishgam appeared to be superior in most of the measured traits. GY showed a positive association with MRN and DRN, which was further supported by principal component analysis aligning GY with root weight, root volume, MRN, and DRN. Despite the advantages and limitations of the pasta strainer method, our results demonstrated that cultivar with deeper rooting type, exhibited better drought performance. https://jast.modares.ac.ir/article_24099_dc7e93f32b3083f13ad7fe95f4966d93.pdf