Correspondence

doi:10.1111/j.1439-037X.2012.00524.x Occasionally, wheat can be exposed to overnight freezing temperatures whilst it is in the early reproductive stage and considerable frost damage can occur. In the vegetative stage, full expression of frost tolerance genes can be gained when plants are exposed to acclimation temperatures (4 °C). Paradoxically, wheat during flowering has limited or no ability to effectively acclimate or re-acclimate and it demonstrates frost sensitivity during this stage. Using a combined approach involving infrared thermography and molecular analysis, the causes and effects of frost-induced damage to wheat during ear emergence were investigated. It was demonstrated that frost damage only occurs to wheat ears if the temperature falls below 5 °C but some ears, and some spikelets on frozen ears do not freeze but supercool and escape freezing. In whole plant freezing experiments, spikelets showed both complete and partial sterility upon maturation and this was linked to parallel infrared observation of detached ears showing full or partial freezin