Effect of Frost on Triticale and Wheat Varieties at Flowering in the North Eastern Australian Cereal Belt

Spring radiation frost is a serious problem in Australia particularly at the reproductive stage, causing an annual revenue loss of more than AU$ 360 million. The focus of frost research therefore has been to identify reproductively frost resistant cereals at the both varietal and species levels that can contribute to alleviating frost damage. Seven triticale and three wheat varieties were assessed to determine relative frost tolerance under natural frost conditions. Plants were grown in pots and raised in the glasshouse. At flowering (±5 days), plants were exposed to a single overnight frost or frost maintained for a short time with varying intensities from 0.2 to –6.6 °C at crop ear height. The frost impact was assessed at maturity based on ear fertility by counting the number of developed grains. There were variable levels of tolerance between triticale varieties with Tahara being more susceptible than other varieties. At species level, triticale was more susceptible than wheat. Temperatures below –3.9 °C were economically damaging. A holistic approach of breeding and agronomic management may be needed to mitigate the frost problem in winter cereals.