Nitrogen utilization efficiency
A better understanding of the mechanisms determining N-utilization efficiency (grain DM yield / above-ground N uptake) including leaf/canopy photosynthesis rate, N remobilization and senescence and their genetic regulation offers scope to increase grain yield, yield stability and GPC under low N conditions. Genetic variation in grain yield in wheat under low N conditions has been associated with senescence parameters linked to post-anthesis N remobilization and QTLs affecting leaf senescence. Improved NUtE of wheat will also require improvement of leaf and canopy photosynthesis rate. There is evidence that there is unrealized genetic potential. N-utilization efficiency will be evaluated for multiple germplasm diversity panels and mapping populations at different N inputs and amounts under standard agronomic systems and rotations as described above. Protocols and data collection will be coordinated by the combined research teams, and the genotyping information used to map QTL in the bi-parental populations and identify marker-trait associations in the association genetics panels, taking into account GxNxE interaction if necessary. The core phenotyping measurements will include plant development (plant emergence and flowering date) and final grain and straw yields and nitrogen measurements.