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Pollinisation inter-parcellaire chez le maïs: analyse et coupage des processus conditionnant la présence du pollen viable en fonction de la distance à la source

Abstract : Coexistence of maize crops involves cross-pollination, governed by wind, which may reduce purity of maize seed productions or lead to transgene dissemination. To reduce cross-pollination, several spatial isolation methods are used (distance, pollen barrier). However, none tool is available for professionals to estimate efficiencies of these isolations methods. This PhD, carried out at INRA (UMR EGC, Grignon, 78) and funded by Arvalis - Institut du vegetal, undertakes to complete and integrate knowledge in an operational model to predict efficient cross-pollination. Its originality is to account for meteorological conditions on an hourly time step over the pollen emission season. The model is built by coupling three sub-models, defining my research axis, predicting: quantity and quality of pollen at emission as well as atmospheric dispersal. Each sub-model is simple and operational based on experimental data mainly collected during my PhD. (1) A statistical analysis of a large dataset collected over 5 years provides a model to predict seasonal and daily patterns of pollen emission. Parameters of these temporal patterns are related to meteorological conditions using a development model and regression trees. (2) Pollen quality corresponds to its viability and its settling velocity. Empirical relationships between these characteristics and water content are estimated from experimental data collected over 2 years. A model has been developed based on these relationships and on existing model of dehydration accounting for air humidity. (3) Modelling of pollen dispersal is based on analytic solution to the advection-diffusion equation found in the literature. It was validated on experimental data collected over 1 year and simulations of mechanistic lagrangian model. The model has been used to compare efficiencies of different isolation methods under contrasted meteorological scenarios by estimating mean percentages of exogenous viable pollen in a receptive field. It reveals that the increasing of cross-pollination when isolation distances are reduced could be compensated by the use of pollen barrier. It also reveals the main effects of wind speed and total pollen productions of coexisting maize crops.
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Submitted on : Friday, January 14, 2011 - 3:39:21 PM
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  • PRODINRA : 246500

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Alexis Marceau. Pollinisation inter-parcellaire chez le maïs: analyse et coupage des processus conditionnant la présence du pollen viable en fonction de la distance à la source. Bioclimatologie. AgroParisTech, 2010. Français. ⟨pastel-00555879⟩

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