Potential impact of elevated atmospheric carbon dioxide and climate change on Victorian wheat marketing grades and value

The potential impact of elevated atmospheric carbon dioxide concentration ([CO2]) and future climate predicted for 2050 on wheat marketing grades and grain value was evaluated for Victoria, Australia. This evaluation was based on measured grain yield and quality from the Australian Grains FACE program and commercial grain delivery data from Victoria for five seasons (2009–13). Extrapolation of relationships derived from field experimentation under elevated [CO2] to the Victorian wheat crop indicated that 34% of grain would be downgraded by one marketing grade (range 1–62% depending on season and region) because of reduced protein concentration; and that proportions of high-protein wheat grades would reduce and proportions of lower protein grades would increase, with the largest increase in the Australian Standard White (ASW1) grade. Simulation modelling with predicted 2050 [CO2] and future climate indicated reduced wheat yields compared with 2009–13 but higher and lower grain quality depending on region. The Mallee Region was most negatively affected by climate change, with a predicted 43% yield reduction and 43% of grain downgraded by one marketing grade. Using 2016 prices, the value of Victorian wheat grain was influenced mainly by production in the different scenarios, with quality changes in different scenarios having minimal impact on grain value.