Dry matter production of winter wheat, cultivars ‘Brennan’ and ‘Revenue’, does not increase after application of gibberellic acid

Winter wheat is often grown as a dual-purpose crop in the High Rainfall Zone (HRZ) of Australia. To help fill the winter feed gap there is grower interest in increasing winter dry matter production for feed without adversely affecting yield. Gibberellic acid (GA) has been used to increase pasture production in winter by stimulating shoot and cell elongation. GA has the potential to be used in dual-purpose winter wheat to increase dry matter production following initial grazing and thereby increase feed supply for subsequent grazing. Adding nitrogen (N) at the time of treatment has been shown to increase dry matter production. Experiments on winter wheat cultivars ‘Brennan’ and ‘Revenue’ were conducted over three seasons (2010 – 2012) in northern Tasmania. Crops were treated with varying rates and combinations of GA and nitrogen (N). Experiments evaluated the individual and combined effects of GA and N on dry matter production and grain yield. Treatments did not increase dry matter yield in these experiments, nor did they adversely affect yield.