ProtNblé

Nitrogen fertilization plays a key role in the wheat production system for its impact on yield, quality and pollution risks. Under conditions of limited nitrogen supply, grain yield, grain quality and the profit margin of the farmers can be significantly reduced. On the contrary, if too much nitrogen is applied, operational costs, nitrogen losses in water or into the atmosphere, root lodging and foliar diseases can greatly increase. Thus, optimising crop yield and quality while safeguarding the environment, is one of the major challenges of modern agriculture. We believe that improving the nitrogen use efficiency (NUE) of wheat cultivars will help reaching this aim. Thus, we propose a comprehensive approach in bread wheat and durum wheat to improve our knowledge of NUE in a reduced N environment. Grain yield (GY) and grain quality assessed by the Grain Protein Content (GPC), will be together considered. The project is structured in different parts. (1) First of all, quantitative genetic studies will be design in order to study the negative relation between GPC /GY but also between N absorption after flowering and remobilization. (2) In the course of an ecophysiological study, N distribution in the plant as determined by plant architecture will be evaluated, and its contribution to the GPC/GY relationship will be assessed and parameters relative to the NUE will be re evaluated; (3) Altogether, quantitative studies, transcriptome analysis, gene mapping and RT PCR will allow to select putative candidate genes (4) Finally, functional validation will be established through association studies using a panel of variety made of tetra and hexaploid wheats. New transgenic lines will also be developed at the end of the project. We aim to identify genotypes, chromosomal regions or genes involved in N management with implication in yield traits.