Germination base temperature and relative growth rate of 13 weed species - comparing populations from two geographical origins

Two experiments were conducted to test parameter validity of a simulation model under North German conditions. At the moment, the model is stocked with life cycle parameters of 25 annual weed species. These were obtained from experiments in the region Burgundy and from literature. Such parameters may vary strongly between geographical regions. Base temperature for germination was studied in one experiment for North German seeds of ten species. Mostly, base temperatures were between 1.5 and 2.7 degrees C higher than the parameters from French experiments. The second experiment, on Relative growth rate of 19 species, yielded similar values for most species in French and German seed populations. In respect to using the model for simulations under North German conditions, adaptations should be undertaken for the germination base temperature. Growth rates can be kept unchanged, but for some species it needs to be clarified whether differences between parameters can be explained through seasonal variations in seed collection or experiment.