Study of the effect of indole-3-butyric acid (IBA) on the rooting of kola tree cuttings (Cola nitida [Vent.] Schott and Endlicher.)

Abstract

The vegetative propagation of the kola tree constitutes a real problem because the plants obtained by cuttings suffer from an imperfect root system, without pivoting axis and sensitive to drought. It is therefore necessary to propose methods to accelerate the growth and root development of kola plants. The objective of this study is to determine the effect of Indole 3-Butyric Acid (IBA) on the rooting of kola tree cuttings and to identify the concentrations favorable to rooting. Cola nitida cuttings from two clones: 313 and D3/2L3A1 were treated with four concentrations of IBA: 0 mg/L, 7500 mg/L; 10,000 mg/L and 12,500 mg/L and transplanted onto a substrate composed of topsoil according to a split-splot device. This study highlighted the significant interaction between IBA and clone on the rhizogenesis of kola tree cuttings. Indeed, the IBA stimulated the rooting while increasing the number and length of the roots of the treated cuttings and the number of new leaves. However, this effect remains clone-dependent. The D3/2L3A1 clone reacts better to IBA for doses of 10,000 mg/L and 12,500 mg/L than clone 313. It should be noted that IBA did not influence the survival rate, the collar diameter, height and biomass. It also appears that the D3/2L3A1 (82.78±12.86%) and 313 (88.34±7.58%) genotypes are suitable for tunnel cuttings. With a view to improving the rooting of kola plants independently of the clone, it would be interesting to test in the nursery Indole 3-Butyric Acid in combination with Indole-3 Acetic Acid and Naphthalene Acetic Acid.