G X E interaction and stability analysis for phosphorus use efficiency in fodder cowpea [Vigna unguiculata L. Walp] using AMMI-based stability measures

Forty-five fodder cowpea genotypes were evaluated under eight different levels of phosphorus fertilization over two seasons, i.e., Rabi 2022-23 and Kharif 2023,, to determine their phosphorus use efficiency. Combined ANOVA revealed the existence of a significant G×E interaction for this trait. AMMI analysis of variance indicated significant variation (p <0.01) among the genotypes (25.11%) and environments (17.25%). The genotype by environment interactions explained 57.35% of total variation, wherein PC1 and PC2 together accounted for 81% of the interaction component. Twelve AMMI-based stability measures were employed to identify stable genotypes. Statistical analysis, such as Spearman’s rank correlation and PCA, suggested absolute value of the AMMI GEI scores (AVAMGE) and the absolute value of AMMI scores for a genotype (Za) could be useful to select phosphorus-efficient genotypes. Comparison of different methods (SI, GSI, SSI) indicated that the genotype selection index (GSI) method of ranking was the best. Genotypes, FD-1161, UPC-801, UPC-2001, EC-107120, UPC-2002, MFC-09-1 and UPC-618 were identified as stable genotypes with high phosphorus use efficiency using GSI & SI approaches.