6533b825fe1ef96bd1281b41

RESEARCH PRODUCT

Flore adventice du tournesol. Quelle évolution en trente ans ? Quelles caractéristiques favorisent la capacité d'infestation des cultures ?

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WEED FLORA EVOLUTION SINCE 1973: WHICH TRAITS SEEM TO HAVE FAVOURED THE CAPACITY OF INFESTING SUNFLOWER? We developed an analysis to pinpoint what biological, ecological or agronomical rules could underline the evolution of sunflower Helianthus annuus L.) weed flora over the past thirty years in France. By separately conducting a clustering of weed species according to their biological similarity and analysing the changes observed in the weed flora at the cluster group level, our approach could highlight beyond the list of species, what set of characteristics seemed to be determinant. The biological milarity between species then allows us to highlight which species could be of major concern in a near future regardless of their actual status. Our study illustrates the running process of specialization of the weed flora now attached to sunflower. In the 70’s, biquitous species already present in the seed bank where the more often encountered. 30 years later, a more specific flora has evolved in sunflower. The capacity of this group of species to mimic the timing of development of the sunflower crop seems to summarize the key characteristics favourable to their successful development. In parallel to that specialized group some more generalist species still maintain their status. The consequences attached to different practices on this evolution is briefly discussed.