Effect of Seed Extraction Period and Germination Temperature on Viability of Pinus patula Under Controlled Conditions
Alice Adongo Onyango *
Department of Natural Resources Management, Faculty of Environment and Resources Development, Egerton University, P. O. Box 536-20115, Egerton, Kenya and Kenya Forestry Research Institute, P.O Box 20412-00200, Nairobi, Kenya.
Shadrack Kinyua Inoti
Department of Natural Resources Management, Faculty of Environment and Resources Development, Egerton University, P. O. Box 536-20115, Egerton, Kenya.
Nelson Maara
Department of Natural Resources Management, Faculty of Environment and Resources Development, Egerton University, P. O. Box 536-20115, Egerton, Kenya.
James Munga Kimondo
Kenya Forestry Research Institute, P.O Box 20412-00200, Nairobi, Kenya.
*Author to whom correspondence should be addressed.
Abstract
A number of coniferous species have demonstrated varied cone responses to the temperature intensities for seed release and subsequent seed germination behaviour. This study investigated the interactions of cone physical characteristics (weight and width), exposure duration (6,12 and 24 hours) at a fixed extraction temperature (65°C) and the germination temperature (22, 27 and 32°C) on seed quality of Pinus patula. The experimental design was a factorial experiment (4×3×3) laid down in a completely randomized design (CRD), with thirty-six treatments replicated 3 times. Analysis of the difference in means from the three factor effects from ANOVA was performed using R Statistical software. Where significant differences were observed, post hoc tests were carried out to separate means using the Tukey test at 5 % significance level. Results showed significant (p=0.001) differences in germination performance as a result of cone characteristics, extraction exposure periods, and germination chamber conditions. Seeds extracted from heavy cones and exposed to germination temperature of 32℃ demonstrated the highest germination percent at 90% while the lowest was 20% from light cones exposed to similar germination temperature conditions. Negative and significant correlation coefficients were observed in germination of seeds from narrow and light cones, thus cone sorting for heavy and wide cones was recommended for better germination performance of P. patula seed germplasm.
Keywords: Pinus patula, cone size, seed exposure, germination, correlation