Evaluation of growth media, seed-sizes and microclimate on sproutability of Tetracarpidium conophorum (African walnut)

Abstract

African walnuts (Tetracarpidium conophorum) are fruits of a woody perennial climber plant with decorative, nutritive, medicinal, agricultural and industrial values. Seed quality, germination medium and environmental condition are some of the key factors of seed germination. This study evaluated the interactions of sowing media, seed sizes and microclimate on emergence of Tetracarpidium conophorum. Seeds of three size categories (Large (<1.5 cm), Medium (1.6-1.90 cm) and Small (>2.0 cm)) were sown into two media (sterilized river sand and treated sawdust). The growth media were placed under three microclimates (open nursery, humid propagator and black polythene cover) and observed for germination. The experiment was laid out in a 3 × 2 × 3 factorial in completely randomized design. The results show that large sized seeds sown in sterilized river sand in the open nursery had 100% germination while the medium sized seeds sown in saw-dust under humid propagator produced the least germination percentage (44.4%). Overall assessment of the experiment therefore showed that large seeds sown in sterilized river sand in open nursery as best for seedling emergence of T. conophorum.