Influence of foliar application of calcium, zinc and boron on fruit drop, yield and quality attributes of aonla (Emblica officinalis) cv. NA-7

Studies on the influence of foliar application of calcium, zinc and boron on fruit drop, yield and quality attributes of aonla cv. NA-7 were carried out during two subsequent years i. e. 2014–15 and 2015–16 on the 15 years old plants of aonla cv. NA-7, located in the garden, Department of Horticulture, Chandra Shekhar Azad University of Agriculture & Technology, Kanpur (U. P.). NA-7, variety of aonla, was tested with the 10 treatments viz., calcium chloride (0.5, 1.0 and 1.5%), zinc sulphate (0.2, 0.4 and 0.6%) and borax (0.2, 0.4 and 0.6%) including a control. Treatments with zinc sulphate @ 0.6% significantly reduced fruit drop 67.21% and increased fruit retention 32.79%, along with higher yield 83.36 kg fruits/plant with more specific gravity 1.10 g/cc, more length 3.91 cm, fruit width 4.04 cm, weight 34.99 g and volume 32.13 cc. Significantly higher pulp weight 33.46 g, pulp: stone ratio 22.91, and reduced amount of titratable acidity 1.47% were also recorded in fruits produced from the plants treated with zinc sulphate @ 0.6%. However, more moisture 94.07%, total sugars 12.93% and TSS 15.10°Brix contents were obtained from borax 0.6% treated plants as compared to control. Whereas calcium chloride @ 1.5% treated plants produced fruits having maximum ascorbic acid 619.33 mg/100 g contents. To obtain higher yield of quality fruits, plants of aonla cv. NA-7 should be sprayed with zinc sulphate and borax each @ 0.6% in the months of August in north Indian plains.