Germination and early heterotrophic growth are the crucial steps in plant establishment. Brunel et al. phenotype several Medicago truncatula genotypes and simulate their germination and emergence under several sowing scenarios using a crop emergence model. Seedling non-emergence is mainly related to mechanical obstacles (40–50 %). More generally, plant parameters that accelerate the emergence time course significantly contribute to limiting the risk of soil-surface crusting occurring before emergence. The model is thus useful in identifying parameters that can be targeted in breeding programmes.