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Present experiment was performed at fruit orchard of Horticultural Research Station, Bahawalpur during 2016-18 to explore optimum concentration of urea causing deblossoming and defoliation in summer crop, subsequently improving fruit quality and production in winter crop of guava cv. ‘Surahi’. Five treatment combinations containing different concentrations of urea applications viz 0% (T0 =control), 09% (T1 ), 12% (T2 ), 15% (T3 ) and 18% (T4 ) which were applied twice fortnightly when summer crop attained 50% blooming. Percentages of flower drop, fruit drop, fruit set and defoliation as well as fruit weight, fruit length & diameter, total soluble solids, acidity, total sugars, ascorbic acid and yield per plant were recorded. Significant differences among treatment combinations were recorded in effect on each parameter during both years of study. Results from combined analysis of two-years data indicated that 15% urea spray on summer crop produced the highest yield (64.83 kg/plant), heavier fruit (203 g), bigger fruit size (length 9.3 cm & diameter 7.5cm), higher TSS (15o Brix), total sugars (7.1%) with minimum acidity (0.65%) in winter crop because of higher flower (75.5%) and fruit drop (41.5%), defoliation (25.8%) and less fruit set (17.7%) compared to non-target summer crop. High concentration of urea (18%) ranked 2nd with respect to fruit and yield parameters of winter crop but it led in flower dropping (80%), fruit dropping (46.8%), defoliation of summer crop (33%) and ascorbic acid (164.4 mg/100g pulp). Urea spray @ 15% proved the best for deblossomig and defoliation of summer crop. [ABSTRACT FROM AUTHOR]

In view of the importance of foliar application of macro and micro nutrients to increase the yield and quality of guava under high density planting system, an experiment was laid out in a randomized complete block design consisting of nine treatment combinations with three replications. [(Control - Fertigation alone), (NPK (19:19:19)), (NPK + Zn), (NPK + Ca), (NPK + B), (NPK + Zn + Ca), (NPK + Zn + B), (NPK + Ca + B), (NPK + Zn + Ca + B). Among the treatments, fruit weight (225.22 g), fruit volume (215.35 ml), number of fruits per plant (80.35), fruit yield per plant(17.67 kg plant-1), TSS(10.60 0Brix), titratable acidity (0.196 %) and pectin content (1.31 %) was found to be significantly higher with the foliar application of NPK @ 1% + Zn @ 0.5 % + B @ 0.4%. The foliar spray of NPK @ 1% + Ca@ 0.2% + B@ 0.4% significantly increased the fruit diameter (7.85 cm), and ascorbic acid content (159.84 mg 100g-1). Thus, foliar spray of NPK, zinc and boron maintained more number of fruits per plant and improved the fruit set leading to an 18% increase in yield. Whereas, the addition of calcium to the plants increased the ascorbic acid content of the fruit and pectin that enhanced the shelf life of the fruit. [ABSTRACT FROM AUTHOR]