EFFECT OF POTASH APPLICATION ON YIELD AND QUALITY OF TOMATO (LYCOPERSICON ESCULENTUM MILL.)

A field experiment was conducted to evaluate comparative effects of sulphate and muriate of potash (SOP and MOP) application on yield, chemical composition and quality of tomato (Lycopersicon esculentum, M. cultivar Roma) at National Agricultural Research Centre Islamabad, Pakistan. Potassium from two sources i.e., MOP and SOP was applied @ 0, 100 and 200 kg K ha(-1) with constant dose of 200 kg N ha(-1) and 65 kg P ha(-1). A significant increase in tomato yield with K application was observed. Potassium applied @ 100 kg K ha(-1) as MOP produced significantly higher marketable tomatoes as compared to SOP and control. Levels and sources of potassium showed no effect on acidity of tomato fruits. Potash application decreased sugar content of tomato fruits as compared to control. This effect of K on reducing sugar content was more pronounced in K treated fruits as SOP than those of MOP. Vitamin C contents in tomato fruits increased with K application in the form of MOP. The K use as MOP significantly reduced incidence of leaf blight disease and insect pest attack in tomato plant as compared to SOP and control treatments.