Germination Response of Juniperus procera Seed to Temperature and Pre-sowing Treatments

Juniperus procera is an indigenous tree species of Ethiopia that has high economic and ecological importance. Propagation of seedlings had poor germination due to dormancy. Enhancing the germination of Indigenous trees particularly, Juniperus procera seeds is the challenge encountered by nurseries. This study was conducted in the laboratory of the Central Ethiopia Forestry Development Center, with the aim to investigate the effect of seed pre-pretreatments (soaking in cold water for 24 hours, scarification, soaking in hot water for10 minutes, and no seed pre-treatment) and temperature regimes (20℃, 30℃, 40℃, and room temperature) on germination. Twenty-five quality seeds per treatment were sown on a petri dish incubated under temperature regimes using a completely randomized design with four replicates. Germination starting and closing dates, germination period, percentages, mean germination time and index were calculated and analysis of variance was done. The result of ANOVA revealed a significant (P<0.05) effect of pre-treatments and temperature regimes on seed germination closing dates, period, percentage and index over the control. There was a non-significant effect of temperature on germination starting and mean germination time. There was also a non-significant combined effect of pretreatments and temperature on the germination period. Among pre-treatments, scarification achieved the best germination and from temperature regimes, 20℃ attained the best result over the other treatments. The highest germination percentage (74%) was obtained under 20℃ with scarification. The lowest germination percentage (18 %) was recorded under the control at 30℃. No germination was observed under 40℃. The shortest germination starting, closing dates and period were obtained under 20℃ with scarification. The lowest mean germination time and the greatest germination index were recorded under 20℃ with scarification. Compared to the control, almost all pre-treatments and temperature regimes increased germination with decreasing temperature regimes. Hence, in raising Juniperus seeds, it is recommended to use scarification under 20℃.