Growth, Yield, and Tuber Quality of Potato with Foliar Application of Tryptophan and Its Derivatives

Document Type : Original Article


Department of Horticulture, Faculty of Agriculture, Ain Shams University, Shoubra El-Kheima, Cairo, Egypt


L-tryptophan as an essential amino acid and its derivatives (indole-3-acetic acid and melatonin) have profound impacts on plant growth and development. In the present study, the aim is to investigate the effect of foliar application of tryptophan, indole-3-acetic acid, and melatonin on vegetative growth, mineral content of vegetative growth, SPAD readings, tubers productivity and quality of potato (Solanum tuberosum L.) plants cv. Spunta. Tryptophan was used at three concentrations (1, 2, and 4 mM), indole acetic acid at three levels (0.3, 0.6, and 1.2 mM), and melatonin at three concentrations (50, 100 and 200 μM), and water as a control treatment.The foliar sprayings were applied three times during the growth period of potato plants; 35, 49, and 63 days after planting. This work was implemented at the Experimental Farm of Horticulture Department, Faculty of Agriculture, Ain Shams University, Shoubra El-Kheima, Qalubia Governorate, Egypt for the two consecutive summer seasons of 2021 and 2022. Results showed that foliar application of tryptophan, melatonin, and indole-3-acetic acid enhanced the vegetative growth, mineral content, and tubers yield and quality of potato as compared to the control treatment. Moreover, foliar application of melatonin at 100 and 200 μM, tryptophan at 4 mM, and indole-3-acetic acid at 1.2 mM showed the highest significant increase in growth, yield, and quality of potato. In conclusion, spraying of melatonin at 100 μM or tryptophan at 4 mM or indole-3-acetic acid at 1.2 mM could be used to enhance growth, tubers yield, and quality of potato plants cv. Spunta.