Influence of naphthalene acetic acid, gibberellic acid and triacontanol on fruit retention, yield and quality of mango (Mangifera indica L.) cv. Banganpalli

A field investigation was carried out on fifteen-year-old mango cv. Banganpalli during 2021-2023 in the coastal region of India at the research farm of ICAR-IIHR-Central Horticultural Experiment Station, Bhubaneswar, Odisha to evaluate the efficacy of some plant growth regulators, namely naphthalene acetic acid (NAA), gibberellic acid (GA3) and triacontanol (TRIA) for improving fruit retention, yield and quality of harvest. The experiment was laid out in randomized block design with 10 treatments consisting of NAA (10, 20 and 30 ppm), GA3 (25, 50 and 75 ppm), TRIA (1, 3 and 5 ppm) and water spray as control. Each treatment was replicated thrice with four plants per replication. Treatments were applied on the plant canopy thrice at panicle initiation, pea and marble stages of fruit growth. Observations were recorded on flowering, fruiting, yield and fruit quality indices. Application of triacontanol at 3-5 ppm brought out a significant improvement over control in terms of panicle size, fruit retention and yield. Plants sprayed with 5 ppm triacontanol produced the largest panicle (length: 29.17 cm, width: 18.07 cm) and recorded the maximum value for fruit retention (68.93, 53.38, 39.41, 32.88, 26.54, 20.46 and 16.58% at 15, 30, 45, 60, 75, 90 and 105 days after pea stage, respectively), number of fruits/tree (104.72) and yield (38.95 kg/tree). With respect to fruit quality, GA3 and TRIA exhibited significant influence on fractions of fruit, dry matter and on most of the chemical attributes (TSS, TSS/acid ratio, total sugar, reducing sugar, non-reducing sugar and vitamin C) when applied at the concentration of 50-75 and 3-5 ppm, respectively.