The grain C:N ratio as an early determinant of the grain nitrogen concentration in contrasting wheat cultivars under different environmental conditions

ABELEDO LG; ALZUETA I; MIRALLES DJ

San Petersburgo

Congreso; 8th International Wheat Conference; 2010

N.I. Vavilov Research Institute of Plant Industry

The importance of wheat (Triticum aestivum L.) as crop is based on its grain quality, which is determined by cultivar characteristics and by the environmental conditions during grain filling. Although grain nitrogen concentration (GNC) is one of the primary determinants of wheat quality, wheat breeding consistently increased grain yield, but this process was in parallel with a significant reduction in GNC. Under water and nutritional potential conditions, actual photosynthesis is the most important source of assimilates during grain filling; while the main source of nitrogen (N) to the grains is the N accumulated before anthesis and that is remobilized to the grains during the grain filling period. The size of the source (i.e. leaf area and leaf photosynthetic capacity), together with the remobilization of assimilates, determine the capacity of the crop to provide assimilates to the growing grains, while the number of grains and its potential size determine the potential capability of the crop to demand assimilates. The balance between the size of the source and the size of the sink determines the source: sink relationship of the crop. In spite of wheat is considered a sink limited crop with low source (carbon) limitation during grain filling, different evidences showed a significant nitrogen limitation during that period. The aim of the present work was to assess comparatively the carbon and nitrogen accumulation in the grains in contrasting wheat cultivars grown under a wide range of environmental conditions.