title: Genotypic variation in the uptake, partitioning and remobilisation of nitrogen during grain-filling in wheat.
abstract: Twenty elite varieties of wheat (Triticum aestivumL.), primarily winter wheat, were grown with low and high supplies of nitrogen (N) in a field experiment at Rothamsted, southern England, in the season 2004-05. The aim was to quantify genetic variation in the uptake, partitioning and remobilisation of N in individual plant organs at extreme rates of N supply. The biggest contibutor to variation in plant and crop performance was 'N-rate' followed by 'growth stage' and then 'genotype'. At both N-rates, there was significant genetic variation in crop performance (grain yield, grain %N, total N-uptake and post-anthesis N-uptake), and in N contents of individual organs at anthesis and maturity, and in N remobilised from individual vegetative organs to the grain during grain-fill. Nitrogen was remobilised from all vegetative organs with very high levels of efficiency by all varieties (80-85%). Stem-N was a major N pool at anthesis probably due to the amounts of soluble N compounds in transit in the vascular system at this time. Despite the genetic variation in N-related plant parameters including stem-N, there were no strong correlations with grain yield and grain %N at a given N-rate. This was probably due to the narrow gene pool employed in this single-season study.
authors.affiliation: Plant Biology and Crop Science Department, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Peter B
authors.initials: PB
authors.lastname: Barraclough
authors.affiliation: Plant Biology and Crop Science Department, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Rafael
authors.initials: R
authors.lastname: Lopez-Bellido
authors.affiliation: Plant Biology and Crop Science Department, Rothamsted Research, West Common, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Hawkesford
keywords: Genotype; Nitrogen; Partitioning; Remobilisation; Uptake; Wheat