Comparative Evaluation of Soybean Genotypes for Yield Potential and Environmental Adaptation across Major Agro-ecological Zones of Punjab, Pakistan

Abstract

Evaluating genotype-by-environment interaction (GEI) and yield stability across diverse regions is critical for releasing well-adapted, climate-resilient cultivars. In Pakistan, domestic soybean (Glycine max L. Merr.) production is constrained by a lack of stable, high-yielding cultivars tailored to contrasting environments. This study evaluated seven soybean genotypes—five promising lines (ORI-Soy-59, ORI-Soy-153, ORI-Soy-146, ORI-Soy-194, and ORI-Soy-25) and two check varieties (Super Soybean and AARI Soybean)—across five distinct locations in Punjab (Faisalabad, Okara, Mandi Bahauddin, Sargodha, and Bahawalpur) during autumn 2025 using a randomized complete block design. The primary objective was to quantify GEI patterns, yield stability, and environmental adaptability using AMMI and PCA biplot models. Genotypic mean yield varied from 1476.6kg/ha (ORI-Soy-25) to 2095.6kg/ha (ORI-Soy-59), while environmental productivity ranged from 1451.71kg/ha (Bahawalpur) to 1900.71kg/ha (Faisalabad). Multivariate AMMI and PCA models captured over 96% of total phenotypic and GEI variation across the first two dimensions. The line ORI-Soy-59 achieved the highest yield 2095.6kg/ha, a near-zero interaction score (IPCA1 = 30.45), and a low AMMI Stability Value (ASV = 814.55), proving superior broad adaptation across environments. Conversely, ORI-Soy-153 and Super Soybean exhibited specific adaptation to favorable, high-input target zones (Faisalabad and Okara), whereas Bahawalpur served as the primary stress-screening location.