Behnam Ababaei1, Bangyou Zheng2, Karine Chenu1*
1 The University of Queensland, the Queensland Alliance for Agriculture and Food Innovation (QAAFI), Toowoomba, QLD 4350, Australia, *Email: firstname.lastname@example.org.
2 CSIRO Agriculture and Food, Queensland Biosciences Precinct, St Lucia, QLD 4067, Australia.
Crop water productivity has been receiving special attention in regards to productivity and food security. Limited-transpiration rate (LTR) at high vapour pressure deficit (VPD) has potential to improve drought adaptation. The quantification of the impact of LTR on water consumption, biomass accumulation and yield formation requires the use of dynamic crop modelling to simulate physiological and environmental processes at a suitable time scale and across environments. Here, a new module for the new generation of Agricultural Production Systems sIMulator (APSIM-NextGen) was developed and evaluated, which enables the simulation of atmospheric (VPD) and edaphic water effects on transpiration, biomass production and yield. The module was used to assess the potential of the LTR trait at improving transpiration efficiency at 60 sites across the Australian wheatbelt. Results showed that selection for the LTR trait could result in a 2.5% increase in grain yield nationally through significantly higher transpiration efficiency. Greatest productivity gains were found in eastern part of the wheatbelt where crops rely heavily on stored soil moisture and saving water mid-day (i.e. under high VPD) allows crops to consume it at more critical stages later during the crop cycle.