Investigating Seed Germination and Early Seedling Development of Selected Moist Forest Timber Species in Umudike, Abia State, Nigeria
A. Asiegbu Esther *
Department of Forestry and Environmental Management, Michael Okpara University of Agriculture, Umudike, Nigeria.
M. C. Dike
Department of Forestry and Environmental Management, Michael Okpara University of Agriculture, Umudike, Nigeria.
O. Duruigbo, Stanley
Department of Wildlife and Range Management, Joseph Sarwuan Tarka University Makurdi, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
This study evaluated seed germination and early seedling growth performance of five economically important tropical timber species such as Irvingia gabonensis, Milicia excelsa, Garcinia kola, Gambeya albida, and Entandrophragma cylindricum, under nursery conditions in Umudike, Abia State, Nigeria. These species are indigenous to the humid forests of West Africa but are currently experiencing population decline due to deforestation and overexploitation. Seeds were subjected to cold-water pre-soaking treatments and sown in sandy clay loam soil. Germination percentage and rate were determined, while early growth parameters including stem height, collar diameter, leaf length, leaf number, and leaf area were measured over a 12-week period. Data were analyzed using analysis of variance (ANOVA) at p < 0.05. Significant variations were observed among species in both germination and growth performance. Milicia excelsa recorded the highest germination percentage (25%) and germination rate (3.57), whereas Irvingia gabonensis and Garcinia kola showed lower germination performance (16.66% and 2.38, respectively). In terms of growth, Irvingia gabonensis exhibited the highest stem height (38.44 cm; 2.53 cm week⁻¹), while Milicia excelsa recorded the largest collar diameter (5.33 cm). Garcinia kola showed superior leaf development, producing the highest leaf number (13) and leaf area (67.26 cm²). In contrast, Gambeya albida and Entandrophragma cylindricum exhibited comparatively lower growth performance. The observed trends indicate species-specific growth strategies and differential responses to pre-treatment conditions. The findings suggest that Irvingia gabonensis and Milicia excelsa are suitable for rapid establishment in plantation systems, while Garcinia kola is better adapted for agroforestry and shaded environments. The relatively low germination observed in some species underscores the need for optimized, species-specific pre-treatment techniques, particularly for recalcitrant seeds.
Keywords: Seed germination, early seedling growth, recalcitrant seeds, tropical timber species, nursery performance, pre-soaking