VEGETATIVE PROPAGATION OF MILICIA EXCELSA BY LEAFY STEM CUTTINGS: EFFECTS OF MATURATION, COPPICING, CUTTING LENGTH AND POSITION ON ROOTING ABILITY

Abstract

The effects of stockplant age, coppicing, cutting stem length and node position on the rooting ability of leafy stem cuttings of Milicia excelsa Welw. were investigated using a non-mist propagation system in Ghana. Four separate experiments tested respectively: (i) cuttings obtained from 1-.2-, 10- and 20-year-old trees, (ii) cuttings from coppice shoots of 1-, 4-and 20-year-old trees, (iii) five length treatments: 3,6,9,12 and 15 cm, and (iv) different node positions. In each experiment, cuttings were treated with IBA and leaf areas were reduced to 20 cm* prior to insertion. Rooting percentages of 65.0% and 11.7% were recorded in 1- and 2-year-old seedlings respectively, while 0% cuttings from 10- and 20-year-old trees rooted. Mortality of cuttings from mature trees was associated with leaf abscission, attributed to the onset of senescence. Rooting ability of mature trees was restored by coppicing, although rooting percentage of cuttings from coppice shoots was still negatively correlated with age of the ortet (r = 0.93, p < 0.05). No significant effect of cutting length oh rooting percentage was recorded, although there was a marked positive correlation between length and shoot production (r = 0.92, p < 0.05). Cutting length was negatively correlated with foliar relative water content (RWC) (r=0.94, p < 0.05). Rooting percentage declined basipetally as a result of increased leaf abscission and lower values of RWC at lower node positions. The practical implications of these findings are discussed.