Evaluation of Genotype x Environment Interaction and Yield Stability of Cotton (Gossypium hirsutum L) Genotypes Under Heat Stress Conditions

The rising levels of CO2 and greenhouse gases in the atmosphere are proving to be a significant concern for cotton crops globally, particularly in Pakistan. It is essential to create resilient cotton cultivars that can tolerate climatic change. However, identification of heat-tolerant and stable genotypes throughout the growing season is a challenging task due to environmental fluctuations. Moreover, due to quantitative nature of heat tolerance, the effect of the environment, and the presence of G x E interaction also pose sudden challenges for identifying heat-tolerant genotypes. In this study, AMMI and GGE biplot analyses were conducted to compare cotton genotypes grown under normal and heat-stress conditions in the field. A comprehensive two-year study assessed the effectiveness of fifteen cotton genotypes and four distinct planting dates. The study involved normal sowing (E1 & E3) and sowing under heat stress conditions (E2 & E4). This research aimed to gather insightful data on how these various factors affect cotton growth and yield. A combined analysis of variance (ANOVA) was utilized to investigate the impact of environment (E), genotype (G), and their interaction (G x E) on cotton genotype yield. Results indicated that all three factors significantly affected cotton yield (P < 0.1%). Further analysis revealed that FH-504 and FH-496 are high-yielding genotypes with greater G x E for normal sowing (E1 and E3) as determined by AMMI and GGE biplots. In contrast, FH-452 was identified as the ideal genotype for heat-stress environment due to its high yield. However, it was also recognized as the least stable due to its high G x E. AMMI and GGE biplots identified FH-Supper Cotton as the best genotype with excellent stability. Overall, these studies provide important information about how to maximize cotton yield and performance under various environmental circumstances. Observations have revealed significant environmental variations in identifying special and general cultivation genotypes. These findings have determined that the E1 environment is most suitable for identifying genotypes with general adaptability, while the E2 environment is best for genotypes with particular adaptability to heat stress. Additionally, both the AMMI and GGE biplot results are consistent with each other.