Physical Seed Quality, Germination and Vigour of Selected Released Cowpea (Vigna unguiculata (L.) Walp) Varieties

Cowpea (Vigna unguiculata (L.) Walp) is an important grain legume in Nigeria and provides food, fodder and income for farmers. Seed quality, particularly germination and vigour, is important for rapid establishment and good crop performance. This study evaluated physical seed quality attributes, germination and vigour of five improved cowpea varieties released by the Institute for Agricultural Research (IAR)—SAMPEA 6, SAMPEA 10, SAMPEA 12, SAMPEA 14 and SAMPEA 20T—and a local cultivar, Danmisra. The experiment was conducted in the Department of Plant Science Seed Laboratory, Institute for Agricultural Research, Samaru, Zaria, in 2021. A completely randomized design with four replications was used. Seed quality attributes evaluated included moisture content, purity, 100-seed weight, broken and immature seed weight, first-count germination, germination index, total germination, seedling length, seedling weight, real seed value and seed vigour indices. Analysis of variance was performed and means were separated using the Least Significant Difference test at the 5% probability level. Correlation analysis was also used to examine relationships among selected seed-quality parameters. The study found differences among varieties in several physical and physiological seed-quality attributes. SAMPEA 10 recorded the highest first-count germination and germination index, while SAMPEA 6 recorded the highest total germination and real seed value. SAMPEA 14 recorded the highest seedling length, whereas SAMPEA 12 recorded the highest seedling weight and seed vigour index II. Overall, the improved varieties generally showed better vigour and germination performance than the local Danmisra cultivar, with SAMPEA 10 and SAMPEA 14 identified in the study as having high seed vigour.