Seed Quality and Longevity of Four Cowpea Accessions in Relation to Seed Coat Colour

Background: Cowpea is one of the most important legumes grown as a sole crop or integrated into farming systems in Africa. Seed quality plays a crucial role in plant population establishment in stressed environment. However, the behaviour of cowpea seeds with different seed coat colours at storage is not known. The study therefore aimed to assess the effect of seed coat colour on seed quality and longevity of seeds of four cowpea accessions. Methods: Two experiments (field and laboratory) were conducted at the CSIR-Plant Genetic Resources Research Institute, Bunso, Ghana for a period of 3 years. Seeds of four cowpea accessions dried to a moisture content of 7% and packaged in aluminium foil packets were stored at -20°C in a deep freezer for 30 months. The quality of stored seeds was measured by seed vigour and germination percentage at 6, 12, 18, 24 and 30 months after storage (MAS). Before storage, the 100-seed weight and initial seed quality were assessed. Result: The study showed significant differences in seed vigour and germination percentage at 6 and 12 months after storage (MAS) among the four cowpea accessions. Light-coloured accessions (GH7175 and GH8800) of cowpea seeds showed higher vigour and were of better quality than those of dark colours (GH3677 and GH2323) at 6, 12, 18, 24 and 30 months after storage.