Effect of Varying Water Temperature on Germination of Selected Tree Species in Delta State, Nigeria

Aims: Effective seed germination is a prerequisite for successful tree planting project. Effect of varying water temperature on germination of selected tree species was examined. Study Design: 4 X 4 factorial experiments in Completely Randomized Design with 3 replicates. Place and Duration of Study: Experiment was conducted in the laboratory of Science Laboratory Technology of Delta State University, Abraka between June 12 and July 26, 2023. Methodology: Twenty-four seeds each of Terminalia mantaly (TM), Senna siamea (SS), Delonix regia (DR), Polyalthia longifolia (PL) were randomly selected and soaked at varying durations in cold-water (120C- 24hrs, 48hrs, 72hrs and 0hrs); warm-water (40oC- 5mins, 10mins, 15mins and 0mins); hot-water (100oC-30secs, 60secs, 90secs and 0secs) and control. A 4 X 4 factorial experiment in Complete Randomized design was adopted. Data on days to germination, sprouts and germination percentage were obtained and analyzed using ANOVA at α0.05. Results: Germination and soaking duration of seeds in cold-water were not significant (P>0.05). Seeds of SS and PL recorded the least and highest days to germinate (11.92±2.31 and 15.30±2.31) and sprout (14.83±2.39 and 18.10±2.39), respectively. One seed each of SS soaked for 24 and 48 hours germinated at day 4 with 66.7% germination (at week 2). Hot-water had significant effect (P<.05) on germination and sprout of seeds while soaking duration and interaction were not significant for germination. Seeds of SS and DR performed best with (6.67±1.33 and 7.58±1.33; 8.42±1.62 and 10.50±1.62) average days to germinate and sprout, respectively. Seeds of SS (60 seconds) and DR (30 seconds) germinated and sprouted within 5 and 8 days with 91.7% germination (weeks 2). Warm-water had significant (P<.05) effect on germination, sprout and soaking duration of seeds. Seeds of SS germinated and sprouted at 6.42±0.78 and 9.57±0.88 days respectively, with earliest days to germinate (5.00±2.22-10mins) and sprout (8.00±2.14- 5mins). DR soaked in warm-water for 10 mins germinated and sprouted within 4 and 8 days after planting. At week 2, seeds of SS and DR had 91.7% germination. Conclusion: Seed pretreatment contributed to the germination of species as no seed was damaged.