Indicators of Drought Tolerance and Water Productivity in Wheat Cultivars Treated via Seed Soaking and Foliar Application of Melatonin and Micronutrients

Abstract A field study was conducted during the 2023/2024 winter growing season in two different locations in Erbil Governorate, Kurdistan Region of Iraq (Ainkawa and Kurdharsha), to investigate the effect of Melatonin and Micronutrients (Zn, Mn, B, Cu, Fe) on drought tolerance indicators and water productivity of two bread wheat cultivars (Haholir2 and Haholir4). The treatments included seed soaking and foliar spraying with melatonin (Concentration 100 μmol L −1 ) and Micronutrients (at a concentration of 1 g L −1 ) at the following levels: (M1) no addition of Melatonin (Mel) or Micronutrients (MN), (M2) seed soaking with Mel, (M3) seed soaking with MN, (M4) foliar spraying with Mel, (M5) foliar spraying with MN, (M6) seed soaking and foliar spraying with Mel, and (M7) seed soaking and foliar spraying with MN. The following indicators were studied: antioxidant enzyme activity (SOD and POD), malondialdehyde accumulation (MDA), water productivity, and grain yield. Results showed that treatments involving both soaking and spraying with Melatonin or Micronutrients were the most significantly effective in enhancing physiological responses and improving yield. The M6 treatment (soaking and spraying with melatonin) reduced MDA levels and increased SOD and POD activity, thereby improving resistance to oxidative stress. Cultivar Haholir4 significantly interaction in grain yield and water productivity at the Kurdharsha Location.