Three environmental indices determine SOC
Unlike previous research, which focused on identifying a single environmental factor to represent environmental mean in studies of phenotypic plasticity (Li et al., 2018, Guo et al., 2020), we uncovered three environmental factors as fundamental to plant growth and development. The inclusion of multiple factors is advantageous for capturing the complex and multifaceted nature of the genotype–environment–phenotype relationship, while also enhancing the accuracy of predicting traits in new environments (Millet et al., 2019). Although these factors are closely related, we did not consider the issue of multicollinearity in this study due to our emphasis on prediction, but it should be taken into account when determining the significance of these factors (Kim, 2019). We demonstrated that environmental factors have various influences on the final phenotype at different developmental phases, particularly the growth windows of 183–192, 166–195 and 144–186 days after planting, which align with the flowering or pod-filling stages of B. napus . It would be ideal to identify specific environmental indices for each genotype (Sabir et al., 2023), but a more practical approach should use a harmonized index shared by all genotypes for prediction and application purposes.