INFLUENCE OF SOWING DATE ON PHENOLOGICAL DEVELOPMENT, GROWTH DYNAMICS, YIELD AND SEED QUALITY OF BAMBARA GROUNDNUT (Vigna subterranea (L.) Verdc.) UNDER RAIN-FED CONDITIONS IN THE NORTHERN GUINEA SAVANNAH OF NIGERIA

Abstract

Bambara groundnut (Vigna subterranea (L.) Verdc.) is an important indigenous grain legume with considerable potential for improving food and nutritional security in Nigeria. However, its productivity is influenced by agronomic practices, particularly sowing date, which determines the environmental conditions experienced during crop establishment, growth, flowering, pod formation, seed filling and maturity. This study was conducted to evaluate the influence of sowing date on the phenological development, growth, yield and selected seed quality attributes of Bambara groundnut under rain-fed conditions in the Northern Guinea Savannah of Nigeria. The experiment was conducted in Bauchi using four sowing dates: early June, mid-June, late June, and early July. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Data were collected on days to emergence, flowering and maturity, plant height, number of leaves, number of branches, number of pods per plant, number of seeds per pod, 100-seed weight, seed yield, germination percentage, and seedling length. The data were subjected to analysis of variance, and treatment means were compared using the Least Significant Difference at the 5% probability level. The results indicated that sowing date significantly influenced the phenological development, growth, yield, and seed quality of Bambara groundnut. Early June sowing generally produced superior performance, recording better crop establishment, greater plant height, higher number of leaves and branches, more pods per plant, higher 100-seed weight, and greater seed yield than the later sowing dates. It also produced seeds with higher germination percentage and longer seedlings. The lowest overall performance was generally recorded under early July sowing. Based on the findings, early June was identified as the most favourable sowing period for Bambara groundnut under the conditions of the study. It is recommended that farmers in the Northern Guinea Savannah should sow Bambara groundnut early in the rainy season, preferably around early June, provided that effective and reliable rainfall has been established. Further studies involving multiple locations, seasons, and Bambara groundnut varieties are recommended to validate the findings under different environmental conditions.