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A crop model component simulating N partitioning during seed filling in pea
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International audience. Seed N concentration is one of the main quality parameters in grain legume crops. Since few studies have aimed at modellingboth seed and vegetative parts N concentrations, our objective was to model N partitioning between vegetative parts and fillingseeds for pea (Pisum sativum L.) in field situations where both N nutrition and the plant genotype varied. A crop modelcomponent predicting the time courses of vegetative and seed N concentrations was built using knowledge concerning Npartitioning during the seed filling period, which include a previously demonstrated relationship between the rate of individualseed N accumulation and the N availability within plants. A greenhouse experiment where assimilate availability was nonlimitingwas conducted with two genotypes. This experiment demonstrated the genotypic variability of one of the crop modelcomponent parameters, the maximum rate of individual seed N accumulation (SNRmax), allowing introduction of this parameterin the crop model component for the studied genotypes. Field experiments spanning 3 years and comprising various crop Nnutrition and four genotypes were conducted to evaluate the crop model component. Observed seed and vegetative parts Nconcentrations ranged at harvest from 19.3 to 39.1 mg g1 and from 3.6 to 18.4 mg g1, respectively. N partitioning was wellsimulated by the crop model component except when crops had deficient N nutrition. These results suggest that the parameter ‘‘NCn-remob’’ (proportion of N in vegetative parts which is not available for remobilization to filling seeds), which is taken as constant in the crop model component, could depend upon the crop nutrition level.A sensitivity analysis highlights the need for a precise calibration of the parameters ‘‘NCn-remob’’ and ‘‘SNRmax’’. When the crop N nutrition level and further genotypic variability of these parameters are incorporated in the proposed crop model component, it will become a useful part of a pea crop model predicting yield and seed N concentration.
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