Assessment of the Responses of Chickpea (Cicer arietinum L.) to the Exogenous Application of Gibberellic Acid and Indole Butyric Acid at Different Crop Development Stages

Background: Chickpea (Cicer arietinum L.) is one of the most important pulse crops in the world. In Tunisia, the chickpea is vulnerable to fluctuation in production in the last few decades. However, phytohormones are known to play crucial roles in regulating different development processes in plants. Methods: This research was conducted in Petri dish and pot experiments in order to determine the effect of gibberellic acid (GA3) and indole butyric acid (IBA) phytohormones on some growth parameters of chickpea. In this study, GA3 at concentrations of 0, 0.05, 0.1, 0.15 and 0.2 g/l and IBA at concentrations of 0, 10-5, 10-4, 10-3 and 10-2 g/l were applied at different stages of chickpea development. Result: Results of Petri dishes trial revealed that IBA (10-4g/l) and GA3 (0.2 g/l) hormones improved significantly the shoot and root length of chickpea plant. Results of pots pointed out that the chickpea achieves the highest plant height when IBA (10-4 or 10-3 g/l) and GA3 (0.2 g/l) were used at pre-flowering stage. The IBA and GA3 application with concentrations of 10-3 g/l and 0.1 g/l, respectively allowed the highest nodule number at post-flowering stage. The parameters number of branches, fresh and dry weight of the aerial part and leaves number were improved in chickpea plants treated with IBA and GA3 at pre-flowering and post-flowering, respectively. Similarly, the number of flowers was promoted by the two hormones. The weight and the number of seeds were significantly enhanced by all IBA treatments in plants. An increase in weight and the number of seeds was observed at post-flowering phase of GA3 treatment. Thus, these results identified the beneficial effect of tested phytohormones in chickpea growth.