Middle-East Journal of Scientific Research 21 (3): 518-524, 2014 ISSN 1990-9233 © IDOSI Publications, 2014 DOI: 10.5829/idosi.mejsr.2014.21.03.21483 Corresponding Author: Rania A. Taha, Biotechnology Fruit Trees Lab., Pomology Department, Agriculture and Biology Research Division, National Research Centre, Dokki, Giza, Egypt. 518 Effect of Different Potassium Fertilizer Forms on Yield, Fruit Quality and Leaf Mineral Content of Zebda Mango Trees Rania A. Taha, H.S.A. Hassan and E.A. Shaaban 1 2 2 Biotechnology Fruit Trees Labortary, Pomology Department, 1 Agriculture and Biology Research Division, National Research Centre, Dokki, Giza, Egypt Pomology Department, Agriculture and Biology Research Division, 2 National Research Centre, Dokki, Giza, Egypt Abstract: This study was carried out during 2011 and 2012 seasons on adult Zebda mango trees 18 years old grown in loamy sandy soil under basin irrigation system in a private farm at El-Sadat district, Minufiya Governorate, Egypt, to investigate the effect of different potassium forms application i.e. feldspar (4800 and 7200 g/tree), potassium carbonate (850 and 1275 g/tree), potassium citrate (1263 and 1895 g/tree) and mono potassium phosphate (1333 and 2000 g/tree) on leaf area, mineral content, fruits yield (kg/tree), fruit physical and chemical properties. Each potassium form was applied in two equal doses; the first rate was added at the second week of February and the second rate was added at the first week of June. Results indicated that all different potassium forms applications had a positive effect on leaf area, mineral content, yield (as number of fruits and kg/tree) and fruit physical and chemical characteristics in comparison with control. Potassium citrate at (1263 and 1895 g/tree) and mono potassium phosphate at (2000 g/tree) were the best treatments to increase leaf area and improve leaf mineral content. In addition, potassium citrate at (1895 g/tree) and potassium carbonate at (850 g/tree) were the most effective treatments in enhancing yield and improved fruit quality as well as physical and chemical properties. Key words: Fruit quality Leaf mineral content Mango Potassium Yield INTRODUCTION fruit drop percentage at different fruit growth stages Mango (Mangifera indica L.) considered the king of under sandy soil conditions are poorly yielded with low fruit in plenty of the countries worldwide. Mango is fruit quality due to lacking their mineral constituents [2]. regarded in Egypt as one of the major local fruit crops and Productivity of several mango cultivars was improved by approximately could be considered the third fruit crop potassium spray [3]. It resulted also in improving the fruit after citrus and grapes. However, mango fruits are quality parameters i.e. TSS %, total sugars and coloration considered as one of the most popular fruits for the [4, 5]. These effects might be dedicated to the potassium Egyptian consumer due to its good flavor, delicious taste, role in increasing tolerance to stresses and improving the nutritive value and other fruit attractive features. It is in formation and accumulation rates of sugars [6, 7]. need to be of wide spreading in Egypt particularly in the Potassium is an essential plant mineral element (nutrient) new reclaimed areas. Mangoes cultivation extended having a significant influence on many human-health rapidly in Egypt to reach 240804 faddan (one faddan = related quality compounds in fruits and vegetables [8]. 0.42 ha) producing 786528 tons and average Although K is not a constituent of any organic molecule production/faddan is 4.29 tons according to Ministry of or plant structure, it is involved in numerous biochemical Agriculture [1]. It is well known that many problems face and physiological processes vital to plant growth, yield, and affect mango productivity i.e. poor fruit set and high quality and stress [9, 10]. especially in the new reclaimed lands. Such trees grow