heat (Triticum aestivum) represents a critical staple crop globally, particularly across Middle East agricultural systems where it serves as the primary carbohydrate source for expanding populations. Contemporary agricultural challenges, including climate variability and demographic pressures, necessitate enhanced productivity per unit area to maintain food security. Plant growth regulators (PGRs) offer promising solutions by conferring resistance to both biotic and abiotic stresses while mitigating environmental stress impacts. This comprehensive two-year field investigation (2023–2024) was conducted at the Iraqi Ministry of Agriculture's experimental facility in Shatrah, Dhi Qar province, employing a randomized complete block design with three replications. The factorial experiment examined three wheat cultivars (Bahooth-22, Aba-99, and Abu Ghoraib) under four growth regulator treatments: control (distilled water), humic acid (5 L ha⁻¹), salicylic acid (1 mM; 138 mg L⁻¹), and potassium iodide (5‰) applied during the stem elongation stage. Statistical analyses revealed highly significant effects (P ≤ 0.01) of growth regulators on spike length, grain number per spike, spike density, grain yield, and weed suppression, with moderate significance (P ≤ 0.05) for fertile tiller count and biological yield. Salicylic acid demonstrated superior performance, achieving maximum grain yield of 5,290.40 kg ha⁻¹. Cultivar effects were significant (P ≤ 0.05) for plant height, grains per spike, spike number, and weed density. Most interactions were non-significant, except for specific year × cultivar and growth regulator combinations affecting tiller fertility and grain yield. The ABA-99 cultivar exhibited superior yield components compared to other tested varieties. Optimal weed suppression occurred with Abu Ghoraib cultivar under salicylic acid treatment (18.125–19.375 g m⁻²). These findings underscore the efficacy of targeted growth regulator applications, particularly salicylic acid and humic acid, in enhancing wheat productivity while mitigating environmental stress impacts in semi-arid agricultural systems.
