Effect of foliar application of Citric and Gibberellic acid (GA3) on growth and fruiting of apricot trees "Prunus armeniaca L." cv. Royal

Abstract

This study was conducted on an apricot orchard in Gradarasha Field Agricultural college Salahaddin university during 2013 -2014 growth season to investigate the effect of Citric and Gibberellic acids on growth and yield of apricot trees "Prunus armeniaca L." cv. Royal. The study consists of two factors: Citric acid foliar sprayed with four concentrations (0, 500, 1000 and 1500 mg.l-1). Gibberellic acid GA3 with three concentrations (0, 25 and 50 mg.l-1). Trees sprayed twice after starting fruit development and 30 days after the first spray. The experiments were designed according to completely randomized block design with four replications and using one tree as experimental unit, While means were compared using Duncan Multiple Range Test at 5% of probability. The impact of foliar spraying with Citric acid significantly increased levels of leaf area and dry weight of the leaves and yield quantitative traits (fruit weight and yield of a single tree in both seasons) compared with the control treatment throughout both seasons. Treatment of foliar spraying with Gibberellic acid GA3 in concentration of 50 mg.l-1 significantly increased leaf area and dry weight in both season, and fruit weight, and holds a single tree in the second season only. The effect of combination between Citric and Gibberellic acids with different concentrations significantly increased the proportion of area leaves, dry weight of leaves, fruit weight and yield of a single tree in the both seasons. The best intervention recorded with Citric acid (500 and 1000 mg.l-1 ) plus Gibberellic acid with concentration of 25mg.l-1 for vegetative traits, while the best intervention recorded with Citric acid 1500 mg.l-1 plus Gibberellic acid with concentration of 25 mg.l-1.