Assessing emergence of bean (Phaseolus vulgaris L.) seed lots in France: Field observations and simulations

In the field experiment, germination rates were always high (80-100%). In contrast, final emergence rates varied from 56 to 90%, emergence lasting from 9 to 28 days. These differences were large between sowing situations but small between seed lots. Emergence was mainly delayed by low temperatures (<10-15 °C) or dry conditions, and emergence rates were reduced to 56% by soil crust formation. When compared to field observations, the model accurately predicted germination while emergence predictions could be improved by including a correction factor that decreased the elongation rate. The simulation study confirmed the results of field observations over a wider range of climatic conditions and with a greater diversity of seed lots. Germination always lasted less than 7 days and was 100% in most cases. Emergence rates reached at least 85% for 75-100% of the years. Differences between seed lot results were mainly due to differences in emergence length of time (6-19 days). The simulations showed that it may be possible to sow earlier than usual in two areas (10-20 days), especially for seed lots with lower temperature requirements. Modelling complemented the field experiments and allowed the risks of different sowing conditions to be statistically estimated. Seed lots industrially processed by seed growers and seed companies should be analyzed using the input variables of the emergence model to determine the variability of their characteristics and their possible influence on emergence.