Effect of Mode of Auxin Application on Rooting and Bud Break of Shea Tree ( Vitellaria paradoxa) Cuttings

Abstract

Vegetative propagation by stem cutting is an important technique applied for agriculturalproduction where rooting success is one of the major aspects. A study to assessthe effects of mode of application of rooting hormones (IBA) on adventitiousroot formation of V. paradoxa stem cuttings was conducted. Accordingly, four applicationmethods were investigated in a 4 × 3 factorial experiment using a CompletelyRandomized Design (CRD). The application methods were: 24-hour extendedsoak, foliar spraying, basal quick dip and delayed IBA application method. Thus, theparameters used to determine rooting success were mean root length and root number.The effect of these application methods on occurrence of bud break was alsoconsidered. On the whole, root length was observed to be a function of IBA concentration,whereby root length increased significantly (P ≤ 0.05) with an increment inIBA concentration. Stem cuttings subjected to 24-h extended soak at 100 ppm rootedbest (59.5% ± 8.33%), where as foliar sprayed stem cuttings exhibited the worstrooting success (11.9 ± 3.06 - 23.8% ± 4.16%). Bud break appeared to decrease withincreasing IBA concentration and delaying IBA application enhanced rooting percentageof the quick dip method by 7.1%, 9.5% and 11.9% at 2500 ppm, 3500 ppmand 4500 ppm, respectively. The extended soak method of IBA application at 80 ppmshows potential for large scale production of V. paradoxa through stem cuttings.