Analysis of Germination-Emergence Phase in Two Legumes (Pea and Bean): Potential and Complementarities of Experimental and Modeling Approaches

Laboratory experiments quantified base temperatures for germination and elongation in peas and beans, revealing that pea germinates below 0°C but elongates only above 2–6°C, while bean requires 7–10°C for both phases. Expressed in thermal time, elongation duration was similar for both species. Winter pea varieties germinated faster than spring types, and seed lots within a genotype showed differences in base and optimal temperatures. The SIMPLE model accurately simulated field emergence except under anoxic conditions. Numerical simulations over 16 years in three French regions demonstrated model reliability for optimizing sowing dates, highlighting the predominant influence of environmental conditions on emergence rates.