DOI: 10.36347/sajb.2018.v06i04.013

Pages: 372-377

Seed dormancy is a challenge in the domestication of Allanblackia floribunda and this has been linked to the presence of abscisic acid (ABA) in the seeds. Recent studies have shown comparable improvement in germination when seeds with thin seedcoat (i.e., extracted from immature fruits) are scarified and soaked for 12 h in water or for 6 h in Fluridone (a chemical inhibitor of ABA biosynthesis). However, it is not known whether prolonged soak in water can stimulate germination in seeds with slightly thickened seedcoat. Also, the optimum soak duration in water is not known for both scarified and un-scarified seeds. Therefore, this study was conducted to determine the effect of a broad range of soak durations in water (0, 6, 12, 24 or 48 h) on the timing and percentage germination of scarified and un-scarified Allanblackia floribunda seeds obtained from immature fruits. The study was arranged as 2 x 5 factorial experiment and analyzed using Survival Data Analysis. The seeds extracted from immature fruits were observed to possess slightly hardened seedcoat and low in moisture content. Radicle and plumule emergence were not observed in un-scarified seeds. Among the scarified seeds, plumule emergence commenced in the control at 77 d after treatment while it was significantly (p<0.05) earlier (56 d) by soaking the seeds for 48 h in water. In all other treatments, plumule appearance commenced at 75-77 d. The highest hazard (plumule emergence) rate was recorded among seeds that were soaked in water for either 12 or 24 h. In these treatments, percentage germination was greater or equal to 50%. Although plumule emergence was earliest with 48 h soak, it reduced the hazard rate at later periods and so, less than 17% of the seeds germinated. The hazard rate in the control and 6 h soak treatments were similar to that observed in 48 h soak treatment.