EXOGENOUS APPLICATIONS OF BORON AND ZINC INFLUENCE LEAF NUTRIENT STATUS, TREE GROWTH AND FRUIT QUALITY OF FEUTRELL’S EARLY (Citrus reticulata Blanco)

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% boricacid + 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 effectivelyimproved the B and Zn level in the leaves, vegetative growth, productivity and fruit quality of Feutrell’s Early madarin.