Leaf Area Index, a good functional trait for screening genetic diversity of Winter Oil Seed Rape response to N constraint : Study of a panel of 95 genotypes

Abstract : Economic competitiveness and environmental sustainability of winter oilseed rape (WOSR) depend on improvement or maintain of the crop yield under low nitrogen (N) fertilisation. Cultivars with higher N use efficiency (NUE) might be characterized (i) by higher leaf expansion and N uptake efficiency until flowering and/or (ii) by longer duration of leaf area (LAI) and photosynthetic activity, and/or (iii) by more efficient remobilisation of N reserves from source leaves to sink organs during reproductive growth phase. We investigated for a large range of WOSR genetic diversity, whether characteristics linked with changes in LAI establishment and duration could be related to high NUE (i.e. high seed yield at low N supply) or N uptake and utilisation.