There is wide spread deficiency of micronutrients in the citrus growing areas of Pakistan. To investigate the influence of foliar application of boron (B) and zinc (Zn), on the leaf nutrient status, tree growth, productivity and fruit quality of Citrus reticulata Blanco cv. Feutrell’s Early, trees were sprayed with boric acid and zinc sulphate either alone or in combination [T1 = control (water spray), T2 = 0.3% boric acid at fruit set stage, T3 = 0.5% zinc sulphate at fruit set stage, T4 = 0.3% boric acid + 0.5% zinc sulphate at fruit set stage, T5 = 0.5% zinc sulphate + 0.3 % boric acid at premature stage)]. Foliar application of B and Zn significantly increased the K, Mn, Fe, B and Zn status of Feutrell’s Early leaves. The application of 0.3% boric acid + 0.5% zinc sulphate at the fruit set stage effectively brought the leaf Zn and B level of Feutrell’s Early mandarin leaves from deficient to optimum range. The tree height, leaf size, fruit weight, juice weight percentage, SSC and TA were also significantly increased with application of 0.3% boric acid + 0.5% zinc sulphate at the fruit set stage. The application of 0.3% boric acid + 0.5% zinc sulphate at pre-mature stage significantly enhanced the concentration of ascorbic in the Feutrell’s Early fruit juice. The total sugars and non-reducing level was also increased with foliar application of B and Zn. In conclusion, the combine application of boric acid (0.3%) and zinc sulphate (0.5%) at fruit set stage effectively improved the B and Zn level in the leaves, vegetative growth, productivity and fruit quality of Feutrell’s Early madarin. Keywords: Boron, Citrus reticulata, Feutrell’s Early, foliar application, fruit quality, leaf minerals, mandarin, vegetative growth, yield, zinc INTRODUCTION Citrus occupies a prominent position in fruit industry of the world and is cultivated on an area of 832.2 thousands ha with 13.9 MT production (FAOSTAT, 2009). Pakistan is among the top thirteen citrus producing countries of the world; having an area of 193.2 thousand ha under citrus cultivation with over 1.47 MT production annually. Punjab province contributes 95% of total citrus production in the country (Anonymous, 2010). At present, among various citrus cultivars being grown in the Pakistan, the Kinnow mandarin is the leading citrus cultivar occupying about 70% share of the total citrus produced (Khan et al., 2010). After Kinnow, the Feutrell’s Early is the only mandarin cultivar commercially grown in Pakistan. The area under mandarin cultivation in Punjab has been increased during the last five years, but average yield per plant per unit area has not been improved. Productivity of citrus trees depends on many abiotic (climate, site, soil, nutrition, and irrigation management) and biotic (rootstock, cultivar, insect pest and disease management) factors (Davies and Albrigo, l994; Iglesias et al., 2007). Among them adequate supply of micro nutrients is most important to produce good quality fruits (Babu and Yadav, 2005; Ioannis et al., 2004). Boron (B) as a micronutrient plays significant role in growth and productivity of citrus. It increases pollen grain germination, pollen tube elongation, consequently fruit set percentage and finally the yield (Abd-Allah, 2006). The B deficiency is mainly found in acidic and sandy soils, and those with low soil organic matter. Plant species differ dramatically in B mobility, and may be classified into species with restricted B mobility and those in which B is highly mobile (Brown and Shelp, 1997). Zn is another important microelement essential for plants due to its involvement in the synthesis of tryptophan which is a precursor of indole acetic acid synthesis. Zn is required for the activity of various enzymes, such as dehydrogenases, aldolases, isomerases, transphosphorylases, RNA and DNA polymerases (Swietlik, 1999). It has important role in starch Pak. J. Agri. Sci., Vol. 49(2), 113-119; 2012 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas.com.pk EXOGENOUS APPLICATIONS OF BORON AND ZINC INFLUENCE LEAF NUTRIENT STATUS, TREE GROWTH AND FRUIT QUALITY OF FEUTRELL’S EARLY (Citrus reticulata Blanco) Ahmad S. Khan 1,* , Waseem Ullah 1 , Aman U. Malik 1 , Rashid Ahmad 2 , Basharat A. Saleem 3 and Ishtiaq A. Rajwana 4 1 Institute of Horticultural Sciences, University of Agriculture Faisalabad, Pakistan 2 Department of Crop Physiology,University of Agriculture Faisalabad, Pakistan 3 Hill Fruit Research Station, Sunny Bank, Murree, Pakistan 4 University College of Agriculture, Bahauddin Zakariya University, Multan, Pakistan * Corresponding author’s e-mail: ahmad_khan157@yahoo.com