Abstract

The effects of different concentrations of indole-3-butyric acid (IBA) on the rooting of leafy stem cuttings of Albizia zygia, Blighia welwitschii, Lophira alata andPterocarpus soyauxii were investigated using non-mist propagators. Four hormone concentrations were used; 16000, 8000, 4000 and 0 µg ml^-1 (control). Results indicated that Albizia, Blighia and Lophira cuttings rooted best when treated with 16000 µg ml^-1 IBA (80, 100 and 40% respectively) and their control cuttings did not root. Pterocarpus stem cuttings treated with 8000 and 4000 µg ml^-1 had 100% rooting while those treated with 16000 µg ml^-1 and control was 80%. The highest root number was noted in cuttings of the various species treated with 16000 µg ml^-1IBA and there were significantly differences only from treatments of Blighia andPterocarpus species. Stem cuttings treated with IBA at 16000 µg ml^-1 also gave the fastest rooting time which ranged from 18 to 78 days. Stem cuttings of Blighia,Albizia and Lophira species treated with16000 µg ml^-1 IBA also had the longest roots (2.48, 1.23 and 1.45 cm respectively). The longest root length of Pterocarpuswas observed in cuttings treated with 8000 µg ml^-1 of IBA (3.72 cm). Vegetative production of seedlings of these species is essential for reforestation programmes.

Key words: Timber species, indole -3- butyric acid, leafy stem cuttings, rooting time, percentage rooting.