Genotype × Environment Interaction for Germination and Seedling Emergence of Bambara Groundnut (Vigna subterranea L.) under Contrasting Agro-ecological Conditions in Nigeria

Abstract

Aims: This study evaluated the effects of genotype × environment interaction on germination rate and days to 50% seedling emergence of 30 Bambara groundnut accessions across three contrasting locations in Nigeria. Study Design:  Randomised complete block design. Place and Duration of Study: Experimental fields of the Department of Biology, Federal College of Education, Okene, Department of Plant Science and Biotechnology, University of Nigeria Nsukka and Department of Biological Sciences, Federal University of Kashere, between June 2026 and July 2026. Methodology: Thirty Bambara groundnut accessions obtained from the IITA GenBank were evaluated across three locations. Thirty treated seeds per accession were planted at each location. Climate variables, including PAR, rainfall, relative humidity, temperature and surface soil wetness, were obtained from NASA POWER, while topsoil (0–15 cm) was analysed for physicochemical properties. Germination percentage and days to 50% seedling emergence were recorded. Data were analysed using ANOVA, LSD (p<0.05), and Pearson correlation. Results: Analysis of variance revealed a significant environmental effect on germination rate, whereas genotype and genotype × environment interaction were not significant. Mean germination was highest in Kogi (99.86%), followed by Nsukka (86.19%) and Gombe (79.33%), demonstrating strong environmental influence on successful establishment. In contrast, genotype, environment and genotype × environment interaction significantly affected days to 50% emergence. TVSu-91 exhibited the earliest emergence (6.44 days), while TVSu-560 was the slowest (11.33 days). Gombe recorded the longest emergence period (9.19 days), compared with 8.36 and 8.27 days in Kogi and Nsukka, respectively. Correlation analysis further indicated associations between germination and climatic and soil properties, particularly radiation, rainfall, soil texture, pH, phosphorus, calcium and base saturation. Conclusion: The findings demonstrate that environmental conditions are critical determinants of germination success, while emergence speed has exploitable genetic and environmental components. Selection for rapid emergence should therefore be conducted across contrasting environments to identify stable genotypes suitable for diverse production conditions.