Evaluation of rooting performance of pinus caribaea cuttings in Uganda

Abstract

For decades, plantation forestry in tropical countries like Uganda has majorly depended on exotic species like pine through exotic imported seeds. However, there has been an increase in failure to meet the current demand for Pinus caribaea seedlings in Uganda because of increased scarcity of quality seeds due to delayed and limited delivery from outside countries among. This study evaluated the possibility of an alternative means of P. caribaea propagation through cuttings to supplement the planting material source. We investigated the impacts of P. caribaea cuttings age, concentration of IBA rooting hormone and the rooting media on optimal performance of P. caribaea cuttings. P. caribaea cuttings were harvested from a two-year-old mother garden with ramets of three different age categories and planted in three different categories of rooting media and hormone concentration at Envirogreen Trust Nursery located in Mukono district. Cuttings were observed for the number of roots developed, root length and root biomass. Data were analyzed using a one and two-way analysis of variance at 0.05 level of significance using Minitab software. It was observed that cuttings rooted in all rooting media used with highest root number and length observed in cocoa peat, but the heaviest roots were in pine bark rooting media. In addition, though the number and length of P. caribaea cutting roots increased with the rooting hormone concentration, root biomass confusingly varied. Furthermore, six weeks old P. caribaea cuttings produced more and shorter roots than those of other ages. The interactions among growth media, cutting age and rooting hormone concentration were significant for root number, length and biomass. Eight-week old cuttings in pine bark medium without IBA showed high performance for number of roots, root length and root biomass. It was concluded that rooting performance of P. caribaea cuttings can be optimized through manipulation of the growth media, cutting age and IBA concentration. It was recommended that an evaluation of the cuttings in both the nursery and the field for survival and growth be conducted. More research about other factors influencing the performance of P. caribaea cuttings such as watering regime and shade intensity should be investigated in addition to the field performance of the plantlets under different environmental conditions.