Association of Gibberellic Acid (GA3) with Fruit Set and Fruit Drop of Sweet Orange

Abstract

To determine the association of Gibberellic acid with fruit set and fruit drop of sweet orange, a research study was conducted at Agricultural Research Institute Tarnab, Peshawar, Pakistan during the year 2012. Three different concentrations(10, 20 and 30ppm excluding control) of Gibberellic acid (GA­₃) were applied as foliar spray at full bloom stage of three different sweet orange cultivars namely Blood Red, Musambi and Succari. Fruit set as well as fruit drop at different developmental stages of fruit were calculated. The results of the experiment revealed that 30 ppm GA₃ application significantly reduced the percent fruit drop, percent June drop and increased yield tree^-1. While fruit set branch^-1, pre harvest fruit drop and fruit weight was significantly affected by 10 ppm GA₃ application. It was concluded from the research study that the foliar application of 30 ppm GA₃ at blooming stage could be applied in order to improve fruit set, control fruit drop and to increase the yield of sweet orange.

Keywords: Gibberellic acid, sweet orange cultivars, Fruit set, June drop, fruit retention, Musambi, Succari, Blood Red.