Potatoe ( Solanum tuberosum L.) is one of the four most important crops with high levels of production in many parts of the world, including Iran. Potatoe is the main vegetable in human food. The dietary and economical importance of potatoe has given this product a special place among agricultural products. Due to this important position, it is necessary to find effective management procedures to increase the production and quality of this crop. Accurate nutrition management is essential for achieving maximum performance. Magnesium fetilization in fields of arid and semi-arid areas of our country due to its native concentration is often neglected and this element assumed as a forgotten element. It is believed that there is a probability of magnesium deficiency due to the high concentrations of potassium and calcium and the depletion of soils during continuous cultivation or intensive use of fertilizers such as ammonium-nitrogen, phosphorus and potassium. In a one-year study, the effects of foliar application of lysine-magnesium and methionine-magnesium aminochelates and magnesium sulfate on yield and quality of three potato cultivars were investigated. Four treatments in each cultivar included magnesium lysine, magnesium methionine, magnesium sulfate and a control using water with three replications. Foliar application was four week after the plants stablishment at four consecutive times with a concentration of 500 ppm. The results showed that leaf applied-Mg in all three cultivars improved potato quality. The results indicate positive effects of magnesium methionine treatment on yield of Arinda cultivar and 20.4% of increase in yield compared to control. Also leaf feeding increased germination and tuber strength after storage in all three cultivars. Leaf feeding also affected the nutrient absorption of potato. The highest weight loss was observed for magnesium sulfate treatment in Arinda cultivar, and the lowest was for the methionine magnesium in Milva cultivar. The highest firminess was observed for magnesium lysine in Marfana cultivar and the lowest was in control of Arinda and Marfana cultivars. Magnesium leaf nutrition reduced the concentration of magnesium in the tuber flesh in two cultivars of Milva and Arinda. In sum, Arinda showd strongest responses and Marfana the weakest responses to the treatments. Among treatments, the most positive effects were related to methionine aminochelate. Keywords Potato, Magnesium, Aminochelate, Lysine, Methionine.
