Skip to Main content Skip to Navigation
Theses

Modélisation de l'effet des systèmes de cultures sur les flux de gènes entre culture transgénique et adventice apparentée. Cas de la betterave sucrière (Beta vulgaris L.)

Abstract : The authorization of genetically modified crops in Europe has been suspended while studying its consequences and management practices. This is the case of GM sugar beet varieties tolerant to a non-selective herbicide. Indeed, there is a risk of gene flow from the crop to wild relatives, i.e. weed beet, frequently found in sugar beet fields. This gene flow would allow the transfer of the herbicide tolerance to the weed beet and thus regress to the current situation or even worse, if the transgene confers a selective advantage to the weed in other crops as well. In order to determine those farming practices that limit or avoid the spread of transgenic weed beet, it is necessary to identify those elements of the cropping systems that influence the demography and genotype of beet population in a region and over the years.
Because of the spatial and temporal dimensions as well as the large range of variability of cropping systems, it is impossible to study the phenomenon exclusively in experiments. Consequently, a model (GENESYS-BEET) was developed to quantify the effects of cropping systems on this gene flow. The model is based on the life-cycle of sugar and weed beet in each field, comprising a succession of life-stages (seedlings, bolters, flowering plants, seed production, seed bank). For each stage are calculated the density of individuals in each field as well as genotype proportions, especially proportions of transgenic individuals. The relationships between the stages depend on the crop cultivated in the field, on the techniques used to manage the crop and on beet genotypes. During flowering, pollen is exchanged between fields and the importance of this dispersal depends on the regional field pattern.
Field experiments were then set up to study and quantify the yet unknown processes of the life-cycle. These trials led to the description and modelling of the evolution of weed beet seeds in soil and assessed in situ seed mortality, seed germination and seedling pre-emergence growth as a function of season. Other trials modelled all key life-stages of weed beet and groundkeepers (bolting proportions and progress, flowering progress, pollen production ....) in the crops most frequently found in sugar beet rotations. Part of the data necessary to construct the model, was taken from literature.
The model was then coded and transformed into a software that was used to run simple simulations to check whether the model integrates the characteristic cropping systems elements correctly, while waiting for the model to be validated and used on a larger scale and in more realistic conditions.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00080792
Contributor : Mathilde Sester <>
Submitted on : Tuesday, June 20, 2006 - 3:30:42 PM
Last modification on : Saturday, June 6, 2020 - 4:52:09 PM
Long-term archiving on: : Monday, April 5, 2010 - 9:27:52 PM

Identifiers

  • HAL Id : tel-00080792, version 1
  • PRODINRA : 252480

Collections

Citation

Mathilde Sester. Modélisation de l'effet des systèmes de cultures sur les flux de gènes entre culture transgénique et adventice apparentée. Cas de la betterave sucrière (Beta vulgaris L.). Autre [q-bio.OT]. Université de Bourgogne, 2004. Français. ⟨tel-00080792⟩

Share

Metrics

Record views

375

Files downloads

240