Germination response of velvet tamarind (Dialium guineense Willd.) seeds treated with pre-sowing soaking in water at varying temperatures and durations

The study evaluated Dialium guineense Willd. seeds response to pre–soaking in water for varying durations and temperature regimes, as a way of addressing the species seed dormancy challenge. Experimental laid out used was 2 x 4 factorial experiment in completely randomized design (r=4). Daily germination counts were taken for ten weeks after sowing. Data were analyzed by use of descriptive statistics and ANOVA at p<0.05. Results showed that germination started within the first seven days after sowing (DAS) for most of the treatments, but was erratic and neither uniform nor massive without effective pre-sowing treatment practice. Only seeds soaked in 75 °C water for 6 hours reached highest 52.5% cumulative germination at 70 DAS, which was followed by seeds soaked in warm water at 45 °C for 6 hours that had 40% cumulative germination. Pre-soaking in water at 30 °C had the least germination performance among the treatments evaluated. Comparison of the two treatment factors (soaking duration and temperature) showed that water at higher temperature regime of 75 °C was most impactful in eliciting improvement in total germination of D. guineense up to 52.5% than soaking duration alone. Six hour soaking gave higher mean total germination (31.4±2.19%) than 12 hour pre-soaking (29.7±4.06%), irrespective of the water temperature. The study has open up opportunity to explore further the optimum higher temperature regimes for pre-soaking in water that will boost massive uniform germination at the earliest possible time; since pre-soaking treatment in water remains safest for both the grower and seed itself among other dormancy breaking methods.