Influence of Bio-regulators on the Fruit Quality and Yield Attributes of Phalsa (Grewia subinaequalis DC)

Aims: To examine the influence of bioregulators on the fruit quality and yield attributes of phalsa.

Study Design: Randomised Block Design.

Place and Duration of Study: Phalsa orchard, Department of Horticulture, Khalsa College, Amritsar during 2015-2016.

Methods: The present study comprised of ten treatments which replicated thrice. The treatments were consisted of Gibberellic acid (GA3 @ 50, 100 and 150 ppm), Naphthalene Acetic Acid (NAA @ 25, 50 and 75 ppm), Ethrel (@ 250, 500 and 1000 ppm) and control. The thirty plants of uniform vigour were randomly selected for the study and these were applied with different concentrations of NAA and GA3 at fruit set whereas ethrel was sprayed at 20 to 25 days before fruit harvest. Uniform sized mature fruits were harvested and a sample of ten randomly selected fruits were being taken from each replication for fruit physical and biochemical analysis and then average was worked out for each parameter. The observations were recorded viz., fruit length (cm), fruit breadth (cm), fruit weight (g), fruit colour, total soluble solids (TSS%), titratable acidity (%), TSS: acid ratio, reducing sugars (%), total sugars (%), ascorbic acid (mg/100 g pulp), stone length (cm), stone breadth (cm), stone weight (g), harvesting span (days), number of pickings and fruit yield per plant (kg).

Results: The results revealed that GA3 150 ppm treated plants yielded fruits with maximum fruit length (1.26 cm), fruit breadth (1.43 cm), fruit weight (1.20 g), reducing sugars (7.49 %), ascorbic acid (31.10 mg/100 g pulp) and yield (3.48 kg/plant). Minimum stone length (0.50 cm), stone breadth (0.33 cm) and stone weight (0.045 g) were recorded in fruits obtained from plants treated with NAA 25 ppm. Ethrel 1000 ppm significantly improved TSS (20.23%), fruit colour (purple black), total sugars (12.79 %) whereas reduced the titratable acidity (1.54 %), harvesting span (22.81 days) and number of pickings (3.90).

Conclusion: The results of the present study concluded that plants treated with GA3 150 ppm registered a significant improvement in fruit physical and biochemical parameters and also fruit yield per plant was increased. The fruits obtained from the plants treated with NAA 25 ppm had small sized and minimum weighed stone. Whereas the yield attributes were enhanced with the application of ethrel 1000 ppm in terms of advancement of harvesting and also reduction in number of pickings. Hence ethrel 1000 ppm may be applied to improve the fruit quality parameters as well as yield parameters and also to fetch the premium price in the market due to their attractive colour appearance than control.