Unveiling the Synergistic Effects of Melatonin and Zinc on Enhancing Yield and Yield Components of Mung Bean (Vigna radiata L.) under Field Condition

The city of Gotvand in Iran is located in a hot and semi-arid region, where it can be challenging to grow crops. Abiotic stresses such as drought and heat can affect crop productivity during both vegetative and reproductive growth. Melatonin plays a vital role in regulating various mechanisms in plants and acts as a primary defense against environmental stresses. However, its interaction with zinc is not well understood. In the experiment, a randomized complete block design with three repetitions was used. A field experiment was conducted to investigate the interaction effects of zinc fertilizer (ZnSO4) - no application, 1 mg/L, and 2 mg/L and different concentrations of melatonin (0, 25,  50, 100, 200 mg/L. Mung bean plants treated with melatonin and higher levels of zinc fertilizer showed increased vegetative growth and improved yield attributes. The specific combination of 200 mg/L of melatonin and 2 mg/L of zinc fertilizer emerges as a promising strategy to maximize yield components, including pod number, seed number per pod, and seed weight. Notably, this combination proved to be the most effective treatment for enhancing mung bean yield formation which resulted in the highest average seed yield to 1764 kg/ha. It is concluded that melatonin and zinc combination is an effective approach to alleviate environmental challenges such as high temperatures during fluorescence and reproductive growth.