Comparative Evaluation of Plant Growth Regulators for Preventing Premature Fruit Drop and Improving Fruit Quality Parameters in ‘Dusehri’ Mango

Abstract

Fruit drop is a major problem resulting in low production and reduction in the income of mango growers in tropical and subtropical regions. Growth regulators, naphthalene acetic acid, gibberellic acid, and 2, 4-dichloro phenoxy acetic acid at the rates of (15, 25, and 35 ppm) were sprayed at full bloom stage on a popular mango cultivar ‘Dusehri’ growing in the subtropical region of Faisalabad in Pakistan. All of the treatments significantly influenced the number of fruits retained at pea, marble, and at harvest stages of fruit growth as compared to the control. Among the treatments, gibberellic acid sprayed at 35 ppm proved to be very effective with 31% more fruit retention than the control. In regard to fruit quality, gibberellic acid (35 ppm) and 2, 4-dichloro phenoxy acetic acid (15 ppm) resulted in a significant enhancement of fruit size in terms of fruit weight (140.8 and 130.1 g), which was 17.6 and 8.7% that of the control (119.8 g), respectively. The treatment 2, 4-D (35 ppm) recorded significantly higher TSS (19.5 °Brix) and TSS to titratable acid ratio over the control. Ascorbic acid content was significantly higher with 35 ppm NAA (61.9 mg/100 ml), while total sugars (20.4%) were significantly higher in 2, 4-D (35 ppm) than the control (11.4%). In general, application of growth regulators resulted in improved fruit retention and fruit quality.