Assessment of canopy growth and development for three wheat cultivars under different water and nitrogen regimes

Traits related to water productivity in dryland cropping interact in multiple ways to influence final grain yield. Crop modelling can be a useful tool to address the challenge of determining how to best combine region-specific traits and develop management adaptation for specific cultivars. The Agricultural Production Systems sIMulator (APSIM) model has been developed and widely-used for diverse applications in scientific research and decision support. However, the model requires further development to accurately simulate important candidate traits associated with water productivity. To better capture differences among genotypes, APSIM needs improvement related to the modelling of canopy development as a driver of water use. Field experiments were conducted in 2015 to assess variation and covariation in traits related to water productivity, e.g. early vigour, tillering, leaf area development, water soluble carbohydrate (WSC) accumulation and transpiration efficiency. Contrasting genotypes for these traits were grown under a range of water and nitrogen regimes. Data were collected through field observation, destructive sampling and highthroughput technologies. Extensive phenotyping was used to explore patterns in canopy development and canopy structure and their impact on productivity, with particular focus on variation occurring during the vegetative stage. An improved wheat model is being developed using the Plant Model Framework in the next generation prototype of APSIM. Experiments described above, as well as previously collected datasets, are being used to develop new algorithms. The new model will be used to assess wheat traits related to water productivity across the Australian wheatbelt