Seed Scarification Improves Physiological Growth and Development of Bambara Groundnut (Vigna subterranea) Depending on Seed Coat Colour

Abstract

This study was conducted to investigate the effect of scarification on bambara groundnut (Vigna subterranea) physiological growth and development and crop phenology. Bambara groundnut landrace seeds used in this study were characterized by seed coat colour (cream, light brown and brown). Seed scarification treatments were mechanical (sand paper) and chemical (sulphuric acid) scarification, while seeds that were not scarified served as a control. A completely randomized design with three replications was used. The parameters that were assessed were time to emergence, final emergence percentage, leaf number, chlorophyll content index (CCI), canopy diameter, plant height, chlorophyll fluorescence (Fv/Fm), photosynthetic performance index (Pi), time to flowering and time to senescence. CCI, leaf number and plant height were significantly (p < 0.05) influenced by seed coat colour, seed scarification treatments and their interaction thereof. Seed scarification treatment had a significant effect on CCI, leaf number and plant height. Generally, seed scarification improved plant overall performance than the control. Chemical scarification presented superior performance of bambara groundnut growth and development. Light brown seeds produced plants with superior overall performance, having superior emergence, CCI, leaf number, and early flowering and senescence. Light brown seeds were followed by cream seeds in terms of superiority of plant performance, having produced plants with superior canopy diameter, plant height and Pi. Therefore, bambara groundnut farmers and researchers can successfully use scarification to improve its physiological growth and attain earlier phenological stages, hence maturity. At the same time, light brown seeds should be selected for cultivation to give the best plant performance.