Grain yield elaboration and nitrogen use efficiency under low N input

Grain yield is a very complex trait in rapeseed, when compared to other crops such as maize or wheat. The complexity is mainly related to the sequential appearance of flowers and then of pods. Therefore, at a given date, flowers, young pods and mature pods can coexist on the same plant. As a consequence, the crop is able to compensate a yield component limitation by another one (e.g., development of extra ramifications when plant density decreases). A given yield can result from different combinations of yield components (number of plants per m², number of pods per plant, thousand seed weight …). Analysis of yield components is currently performed under different nitrogen nutrition conditions.

Research

Our research focusses on:

• Genetic variability of the crop adaptation to low N input (in terms of biomass, leaf area index, pod area index, nitrogen harvest index)
• Genetic and molecular analysis of yield establishment under low N input

Main results

Recent years have mainly allowed the development of experimental systems and phenotyping tools as well as the exploration of the existing genetic material in trials conducted in controlled or field conditions. Genetic analysis is being developed and has led to the identification of QTL for oil yield, yield components and NUE parameters. Some of the variables are also being acquired at key stages on a panel of genotypes to initiate an association analysis.

Fundings/Projects

• ARCOLE (ANR Genoplante 2006-2008): « Efficacité de la nutrition azotée du colza au printemps : identification de cibles de sélection » (coordination X. Pinochet, CETIOM)
• GENERGY (ANR Genoplante 2008-2012): « Improvement of the oil yield of the rapeseed crop in the context of bio fuel production » (coordination N. Nesi, INRAE Rennes)
• RAPSODYN (Investissements d’Avenir 2012-2019): « Optimisation of the rapeseed oil content and yield under low nitrogen input : improving breeding of adapted varieties using genetics and genomics» (coordination N. Nesi, INRAE Rennes)