Improved temperature and photoperiod response functions to better link genotype to phenotype prediction for soybean phenology.

Soybean phenology responses to temperature and photoperiod were quantified across 20 modern cultivars (MG 0–7), yielding optimum temperatures declining from 30.4 to 22.1 °C.

• Why it matters: Existing soybean phenology models use older datasets with limited genotypic coverage and omit twilight effects, limiting robust genotype-to-phenotype prediction.
• What they did: Responses for emergence–flowering, flowering–beginning seed filling, and beginning seed filling–physiological maturity were reconstructed from 12 controlled-environment and 13 USA field experiments, using curvilinear temperature and bilinear photoperiod models.
• The result: Prediction accuracy across independent USA field experiments was maximized with a twilight angle of -6°, where an uncalibrated multiplicative model achieved RMSE 0.96.