Yield stability of groundnut genotypes across contrasting environments in Niger using GGE biplot analysis

Groundnut (Arachis hypogaea L.) productivity in Niger remains low despite its potential, mainly due to erratic rainfall, poor soil fertility, and disease and pest pressure. This study aimed to quantify the effects of genotype, environment, and genotype × environment interaction (G × E), evaluate yield performance and stability, and identify superior genotypes and optimal test environments. A total of 21 groundnut varieties were evaluated across four environments (two locations over two years) during the 2021 and 2022 cropping seasons. Genotype plus genotype × environment interaction (GGE) biplot analysis was used to assess stability and adaptability. Analysis of variance showed significant genotype × environment interaction for pod yield (p < 0.01), while genotype and environment effects were highly significant (p < 0.001) for most agronomic traits. Mean pod yield ranged from 1915.22 kg/ha for Diankadapé to 2990.10 kg/ha for ICGV 93,305, with a grand mean of 2517.26 kg/ha. The highest-yielding genotype, ICGV 93,305, exceeded the grand mean by 18.78% and the lowest-yielding genotype by 56.12%. Other high-yielding genotypes included ICGV-IS 13,989 (2945.88 kg/ha), ICGV-IS 14,857 (2846.22 kg/ha), Pyr-370 (2774.10 kg/ha), and Rafeet Car (2772.55 kg/ha). The GGE biplot explained 80.85% of the total G + GE variation, with PC1 and PC2 accounting for 58.52% and 22.33%, respectively. The mean-versus-stability view identified ICGV-IS 13,989 and SH470P as the most stable genotypes, while the ideal-genotype ranking indicated Rafeet Car, ICGV 93,305, ICGV-IS 13,989, and ICGV-IS 14,857 as desirable genotypes. Environment E1 was the most discriminating and representative test environment. These findings identify stable and high-performing groundnut varieties for varietal recommendation and future breeding in Niger.