Influence of gibberellic acid, naphthalene acetic acid and borax on fruit drop, retention, cracking and quality attributes of litchi cv. Rose Scented

An experiment was conducted on 64-year-old well-established, healthy, and uniform trees of litchi cultivar cv. Rose scented in the garden, Department of Horticulture, C. S. Azad University of Agriculture and Technology, Kanpur (U.P.) using ten treatments viz., T₁-GAƒ @ 10 ppm, T₂-GAƒ @ 20 ppm, T₃-GAƒ @ 30 ppm, T₄-NAA @ 10 ppm, T₅-NAA @ 20 ppm, T₆-NAA @ 30 ppm, T₇-borax @ 0.4%, T₈-borax @ 0.6%, T₉-borax @ 0.8% and T₁₀-control or water spray, in Randomized Block Design (RBD) and replicated thrice. One plant was taken as a unit per treatment. Plant growth regulators and micronutrient were sprayed before flowering on 24th February 2024 and secondly at the pea stage on 19th March 2024. Based on the data findings, it was reported that the foliar application of plants with various levels of plant bio-regulators and Borax significantly influenced fruiting behavior and quality attributes of litchi fruits. The treatment of plants with NAA at 30 ppm concentration results in considerable increase in fruit set (62.10%), fruit retention (60.24%), fruit length (4.00 cm), fruit width (2.80 cm), fruit weight (12.67 g), pulp weight (8.86 g), pulp: stone ratio (4.40), TSS of fruits (19.46°Brix), total sugar content (18.34%) with highest TSS: acid ratio (46.33) and sugar: acid ratio (43.67). The same treatment also significantly reduced the fruit drop (39.76%) percentage, stone weight of fruits (2.01 g), peel weight (1.80 g) and titratable acidity content (0.42%). However, the percentage of cracked fruits was considerably reduced (6.00%) with the foliar application of borax at 0.4. Strong positive correlations were observed between fruit weight and pulp weight (r = 0.99), TSS and total sugar (r = 0.96), and TSS and fruit retention (r = 0.94). Titratable acidity showed a strong negative correlation with sugar: acid ratio (r = -1.00) and TSS: acid ratio (r = -1.00) under the North Indian plains of U.P.