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Dernière mise à jour : Mai 2018

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UMR ECOSYS - Ecologie fonctionnelle et écotoxicologie des agroécosystèmes

Poster 3 : Colza_densite

Poster 3 : Colza_densite.
A. Mathieu, A. Julien, J.M. Allirand, M. Bidon, F. Duhamel

Caracterization of Winter Oilseed Rape response to density and initial conditions

 

Plant plasticity is the capacity for a plant to adapt to its environmental constraints. A better understanding of winter oilseed rape plasticity may help to explain plant functioning and to predict plant behaviour in a changing environment. Due to this plasticity, there is a great variability between plants within a crop expressed by different features of architecture, among which the number of leaves and branches. Our objective is to understand how this variability takes place. In this article, we focus on the vegetative part of the crop cycle and simple architectural variables

One cultivar (Pollen) have been grown in ten square containers in order to control growth conditions (Grignon, France, 2012-2013). Plants were sowed in buckets and transplanted two weeks later at two densities with a regular distribution pattern. At the highest density, there was two treatments: homogenous and heterogeneous. The pattern of distribution of heterogeneous plants was predefined in order to study different types of neighbourhood. Once a week from September 2012 to April 2013, the number of leaves by plant was counted and plants were photographed to compute green surface area. Besides, four destructive measurements have been carried out: initial stage, end of winter, end of branch appearance, flowering stage.

A great variability in the leaf dynamics was observed even within a pot, whatever the treatment. The number of final leaves ranges from 14 to 32. Considering only the heterogeneous experiment, initial plant size explained 30% of the variability of final leaf number. There is a significant effect of the initial size on phyllochron too. The ranking of plant phyllochrons remained constant over time, meaning the heterogeneity was maintained during the growth, without visible rebalancing effects between plants. Next step of this work is to study neighbourhood effect between plants using photographies. This study may help to better understand interactions between plants within the crop. These results will be used to validate a functional-structural plant model of WOSR and extend it from individual plant to population of plant level.