Ashiru Ibrahim

Nigeria

COMPARATIVE STUDY OF GERMINATION, SEED DORMANCY BREAKAGE TREATMENTS AND SEEDLING GROWTH OF TAMARINDUS INDICA.

Ashiru. I. Ijinga1, Umar. U. Uwais2, Mahmoud Dogara2

1. Department of Biological Sciences, Kaduna State University, Kaduna State, Nigeria
2. Department of Biological Sciences, Kaduna State University, Kaduna State, Nigeria
2. Department of Biology Education, Tishk International University, kudistan iraq

Abstract

Background

BACKGROUND: Tamarindus indica, an indigenous tropical legume fruit tree, is widely recognized for its nutritional, medicinal, and socioeconomic value; however, it remains significantly underutilized despite its broad ethnobotanical relevance. The species contains numerous bioactive compounds with well-documented therapeutic properties, making it an important resource for communities that depend on traditional medicinal systems. In many tropical regions, T. indica has the potential to address nutritional deficiencies, enhance community health, support local industries, and contribute to ecosystem resilience. Yet, despite its ecological and economic importance, its propagation is severely constrained by intrinsic seed dormancy. A substantial proportion of seeds produced in the wild are lost to predation, environmental disturbances, and unfavorable storage conditions, while the remaining viable seeds often fail to germinate due to hard, impermeable seed coats that inhibit water uptake and embryo expansion. This biological limitation reduces natural regeneration, weakens population stability, and restricts large-scale cultivation. As a result, there is growing scientific and agricultural interest in identifying efficient, reproducible, and cost-effective dormancy-breaking methods capable of improving the germination success and early growth performance of T. indica.

Methods

METHODS: This study employed a comparative experimental design to evaluate the germination response and seedling vigor of Tamarindus indica seeds subjected to three major dormancy-breaking treatments: distilled water soaking, hot-water immersion, and sulfuric acid (H₂SO₄) scarification using concentrations ranging from 10% to 50%. Seeds were first categorized into viability groups based on color and morphological characteristics. Laboratory germination tests were conducted using Petri-dish plots under controlled conditions, while seedling vigor assessments were performed in nursery plots arranged in a Completely Randomized Design. Seeds exposed to sulfuric acid were treated for standardized durations, followed by thorough rinsing and transfer to moistened germination media. Parameters evaluated included germination percentage, rate of emergence, vigor index, uniformity of sprouting, and visible changes in seed coat permeability.

Results

RESULTS: Preliminary findings indicate significant variability in germination performance across treatments. Sulfuric acid scarification produced the most pronounced improvement in seed coat softening, facilitating rapid imbibition and early radicle emergence. Seeds treated with moderate concentrations of H₂SO₄ (20–40%) exhibited the highest germination percentages, faster emergence times, and more vigorous seedling development compared with distilled-water and hot-water treatments. Distilled-water soaking showed minimal improvement, while hot-water treatments produced inconsistent results, likely due to sensitivity to temperature fluctuations. Viability groups based on seed color showed clear differences in responsiveness, with normal brown seeds demonstrating the strongest germinative potential.

Conclusions

CONCLUSIONS: This comparative study demonstrates that chemical scarification using sulfuric acid is a highly effective pre-sowing treatment for overcoming Tamarindus indica seed dormancy. The method consistently enhances germination percentage, reduces emergence time, and improves early seedling vigor more effectively than water-based treatments. Establishing a standardized acid-scarification protocol will significantly support large-scale propagation efforts, improve conservation outcomes, and expand the commercial availability of T. indica. These findings highlight the importance of adopting scientifically validated dormancy-breaking methods to ensure sustainable utilization, increase productivity, and maintain the ecological and economic value of this culturally important species.